Over the past couple of years, my research interests have evolved and expanded. While I maintain interest in understanding the dynamics of tropical cyclones and techniques that can be used to improve forecasts, most of my recent research is more broadly focused in tropical meteorology. Deep thunderstorm (or convective) activity occurs often in the tropical environment, and clouds that extend to the top of the troposphere spread out laterally and form anvil clouds that are composed largely of ice particles. These anvil clouds survive for longer than the parent thunderstorm and can have measurable effects on radiative transfer in the troposphere. In mesoscale convective systems (MCSs), the deep thunderstorm activity often develops into a cohesive squall line, which is then trailed by a large area of lighter precipitation and a broad shield of ice anvil clouds that trails the whole system. Part of my research has been to quantify the effects of these anvils on radiative heating in the atmosphere using data from cloud radars run by the US Department of Energy. We can then compare the heating generated by anvil
What are the impacts of this Addu anvil cloud on radiation and moistening of the troposphere?
clouds to latent heating produced by the precipitating areas of an MCS. We may also compare the structure of anvil clouds and precipitating areas in a high-resolution mesoscale model to those that we have observed. A correct model of the anvil can provide us some additional physical insight into how it is formed and maintained. By repeating this process for several different areas of the tropics, we learn of the differences between anvil structures over continents and over oceans.
In September 2011, as part of a large field campaign, I traveled to the Maldives, which are located south of India in the central equatorial Indian Ocean. Specifically, I was among many of the personnel located at the radar "supersite" on Addu Atoll. The project, known as CINDY2011/DYNAMO/AMIE (different titles by different agencies), aimed to gather in-situ atmospheric and oceanic observations over the central Indian Ocean and surrounding domain between October 2011 and February 2012. Using the wealth of data collected, we aim to examine the relative roles of large-scale tropical dynamics and the cloud population to moistening of the troposphere prior to the onset of a Madden-Julian Oscillation (MJO). The MJO has important impacts on weather, such as tropical cyclone activity, as it propagates westward around the globe from its origin in the Indian Ocean. However, due to our current limited understanding of the initiation process, our computer models do not properly simulate the MJO. Many questions remain as we begin digging into the dataset. Why does an MJO initiate at some times and not at others, when conditions, at first glance, appear the same? How important are cloud moistening processes, such as evaporation or sublimation of anvil clouds, in MJO initiation? How variable is the humidity on temporal and spatial scales over the tropical ocean? Can this variability be reliably observed in situ by a radar system?
...Ernesto makes landfall--for the fifth and final time--as a borderline tropical storm/Category 1 hurricane near Cape Fear, NC...
Although these forecasts appear statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
The eye of Ernesto came ashore just west of Southport, NC, at around quarter to midnight Thursday night. Ernesto has reached its maximum strength, and surface observations will indicate whether or not the storm had made it to hurricane intensity prior to landfall. Based on aircraft data and continuity, initial intensity is 60kts. Radar banding is very well defined, with a very dense band of heavy convection extending to near New Bern, NC, and then a smaller eyewall north of Wilmington. The strongest portion of the storm is confined to this eyewall in the northeastern quadrant of the cyclone. Ernesto is moving quicker than the previous forecast indicated, so this track is sped up to accommodate the current motion. Ernesto should be extratropical within 36 hours and absorbed by Day 3.
INIT 34.2N 78.2W 60KTS...INLAND NEAR WILMINGTON, NC
12HR 36.2N 77.2W 40KTS...INLAND NEAR HALIFAX, NC
24HR 37.9N 77.3W 30KTS...INLAND OVER EASTERN VA
36HR 40.0N 77.6W 20KTS...INLAND/EXTRATROPICAL
48HR 42.0N 78.5W 20KTS...INLAND/EXTRATROPICAL
72HR...ABSORBED
statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
NOAA aircraft has indicated that winds within Ernesto have increased to 60kts, and SSD objective intensity estimates are 4.0, or 65kts, which would support a hurricane. Microwave and visible images show much better organized banding. Environmental flow over Ernesto is favorable, and upper level analysis from UW-CIMSS shows a anticyclone off-center from the circulation. Additionally, an eye may be forming beneath the high cloud tops visible on satellite. Given favorable conditions and a few more hours over water, Ernesto is forecasted to become a hurricane prior to landfall. Otherwise, there is not much difficulty left that Ernesto could give us--it will make landfall, destined to never move over open ocean again, and will weaken while becoming extratropical over the interior northeastern United States. Ridging will trap the storm and slow it down, which could result in heavy amounts of rainfall over the mid-Atlantic and central Appalachian mountains. The forecasted landfall intensity is 75kts. This is not indicated in the forecast since Ernesto will make landfall within 12 hours. Pressure continues to fall, and a combination of baroclinic interaction and internal processes will support rapid intensification, much like was seen with Hurricane Alex in 2004. A hurricane warning is reccommended for the upper SC coast and southern NC coast.
INIT 32.2N 78.9W 60KTS
12HR 34.2N 78.3W 70KTS...INLAND OVER SE NC
24HR 36.5N 78.0W 40KTS...INLAND NEAR NC/VA BORDER
36HR 38.5N 78.0W 30KTS...INLAND; BECOMING EXTRATROPICAL
48HR 40.5N 79.0W 20KTS...INLAND; EXTRATROPICAL
72HR...ABSORBED
...Ernesto emerging over the Atlantic Ocean near Cape Canaveral...
Although these forecasts appear statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
NWS radar out of Melbourne, FL, shows that center of Ernesto is emerging over water near Cape Canaveral. The cloud pattern remains organized on infrared imagery tonight, and central pressure has actually fallen a little while Ernesto has been over land. The storm will soon have warm waters to work with and favorable southwesterly flow--provided that the flow is not too strong. Baroclinic interaction is also fairly likely ahead of troughing, and Ernesto will probably soon become a tropical storm again. The forecast track has shifted a little to the east, and the storm could have up to 24 hours over water. Since the center of circulation remains intact, I will allow for intensification back to 50kts. SHIPS with decay only brings the storm to 38kts prior to landfall; however, environment flow may do more help than harm in this situation. The track, as mentioned, is nudged slightly west, but is generally along the same track and near CONU.
INIT 28.7N 80.6W 30KTS...OVER WATER NEAR CAPE CANAVERAL, FL
12HR 31.0N 79.8W 40KTS
24HR 33.3N 79.0W 50KTS...OFFSHORE NEAR GEORGETOWN, SC
36HR 35.5N 78.5W 30KTS...INLAND NEAR RALEIGH, NC
48HR 38.4N 79.0W 20KTS...INLAND; BECOMING EXTRATROPICAL
72HR 42.0N 80.0W 20KTS...INLAND; EXTRATROPICAL
96HR...DISSIPATED
...Ernesto weakens to a depression over the Florida peninsula...
Although these forecasts appear statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
Ernesto has weakened below tropical storm status based on ground observations this morning, and initial intensity is 30kts. The low-level circulation remains intact; however, there is very little thunderstorm activity near the center. Some strengthening is possible after the storm emerges over water later tonight and has between 12 and 24 hours over water. The forecast allows Ernesto to become a tropical storm before landfalling in the Carolinas--probably along the South Carolina coast. Track reasoning remains unchanged; although, guidance diverges significantly after 48 hours. Ridging will build north of and around Ernesto, trapping the storm inland over the mid-Atlantic and northeastern US. The track is near the CONU ensemble and shows a bend back westward after two days. Ernesto should eventually dissipate over land, and this is indicated at Day 5.
INIT 26.8N 81.0W 30KTS...NEAR LAKE OKEECHOBEE
12HR 28.8N 80.9W 30KTS...NEAR NEW SMYRNA BEACH
24HR 31.5N 80.1W 35KTS...OVER WATER
36HR 34.1N 79.3W 45KTS...INLAND OVER NE SC
48HR 36.7N 79.6W 30KTS...INLAND
72HR 40.0N 80.5W 20KTS...INLAND; BECOMING EXTRATROPICAL
96HR 42.5N 81.5W 20KTS...EXTRATROPICAL; DISSIPATING
120HR...DISSIPATED
...Much ado about nothing; Ernesto making landfall as a weak tropical storm...
Although these forecasts appear statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
The center of Ernesto is coming ashore between Islamorada and Key Largo in the Florida Keys and will soon cross Florida Bay and enter the southern Florida peninsula. Forward speed is slowing, and a turn to the north will occur soon. Maximum winds are no more than 40kts; the center has recently shown more banding and organization on local NWS radar and may have been slowly intensifying. Today, the center of circulation has not organized much though, perhaps due to a little easterly shear from anticyclonic flow. Ernesto will cross the Everglades, but the intensity will lower as the center moves over the peninsula. The forecast brings Ernesto to tropical depression status before re-emerging over water, and does not anticipate a major event for the Carolinas--a hurricane is now quite unlikely. Model guidance keeps Ernesto near the coast as it moves toward the Carolinas, away from the warmest water in the Gulf Stream farther offshore. Still, until North Carolina, waters immediately offshore are plenty warm to support intensification and with southerly and southwesterly flow guiding Ernesto at the mid and upper levels, the storm should intensify. SHIPS brings the storm back to 40kts with decay over land factored in. The forecast will allow the storm to reattain 50kts, lower since it is currently weaker and will remain over Florida for almost 24 hours, but as strong as predicted since the LLC will not be disrupted as it was over Cuba.
INIT 25.0N 80.5W 40KTS...NEAR ISLAMORADA, FL
12HR 26.3N 81.0W 40KTS...OVER EVERGLADES
24HR 28.9N 81.0W 30KTS...NEAR DAYTONA BEACH, FL
36HR 31.3N 80.2W 40KTS...OVER WATER
48HR 33.6N 79.5W 45KTS...INLAND OVER NE SC
72HR 39.0N 79.0W 25KTS...OVER NE W. VA
96HR 42.0N 79.0W 20KTS...DISSIPATING OVER SW NY
120HR...DISSIPATED
...Ernesto crossing the Florida Straits and trying to organize...
Although these forecasts appear statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
RECON has found a better organized Ernesto this morning with falling pressure. SSD estimates are 35kts, and RECON has not found winds to support any more than 35kts, so that is the initial intensity. Banding features are trying to take place, and Ernesto should intensify before making landfall. It is possible that the storm could become a hurricane before landfall, but this is not indicated by any guidance now, and SHIPS only brings it to close to 50kts. Visible satellite has shown better presentation at the low levels this morning, and Ernesto has plentiful warm water and low shear to work with before making landfall. The forecast brings the storm to 50kts at 12 hours, but I would not be surprised to see 55kts or 60kts in an isolated location at landfall. The track forecast is along the same line as previous up to 48 hours, but is shifted west with model guidance afterward. Ridging will build in north of Ernesto after a trough passes, allowing the storm to turn north and even add a little westward component to the motion. The track takes Ernesto into Canada as a weakening extratropical cyclone. Since the track has shifted west, a hurricane is not forecasted for North Carolina; however, if the storm moves farther off the East Coast, then it will pass over the Gulf Stream instead of cooler waters closer to the coast. Conditions and environmental flow would be conducive to strengthening.
INIT 23.4N 79.6W 35KTS
12HR 24.8N 81.0W 50KTS
24HR 26.5N 81.5W 50KTS...INLAND, SW FL
36HR 28.9N 81.2W 40KTS...INLAND, NE FL
48HR 31.6N 80.4W 45KTS...OVER WATER
72HR 36.5N 79.0W 30KTS...INLAND NEAR NC/VA BORDER
96HR 40.0N 79.5W 20KTS...INLAND OVER SW PENN; REMNANT LOW
120HR 44.0N 80.0W 20KTS...INLAND OVER CANADA; EXTRATROPICAL
...Ernesto slowly moving off of Cuban coastline...
Although these forecasts appear statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
The center of Ernesto--or what is left of it--appears to be emerging off the coast of Cuba. SSD gives T3.0 and a center just offshore. Convection has increased some over water as the center skirts the coastline, and although the LLC seems greatly disrupted, it should be able to reform beneath the MLC as it moves over water. This, however, will keep Ernesto weaker than once anticipated. SHIPS initializes at 35kts off of RECON, and only brings it to near 45kts before landfall shortly after 24 hours. Track guidance has shifted left, and Ernesto is currently moving left of the previous forecast, so a shift is necessary. Guidance is very clustered through 3 days, taking the storm into the Carolinas. Since convection is continuing, I am a little more aggressive, giving the storm 50kts before landfall in a low shear environment; vertical shear is 10kts or less. If Ernesto re-emerges over water as it moves northeastward, it will have the Gulf Stream and favorable upper level winds to work with, and intensification is likely. It is possible that Ernesto may not strengthen into a hurricane before hitting Florida, but may impact the Carolinas as a hurricane. Most guidance has Ernesto crossing Florida in less than 24 hours, and the track is far enough east to put the storm over water, so I bring the storm to minimal hurricane status before hitting North Carolina. Flow from an approaching trough to the west may aid the outflow of Ernesto resulting in intensification. Of course, forecast confidence is low, and a track over land would eliminate any chance of strengthening. GFDL strangely is the only model as of recent to bend the track back westward late, resulting in a CONU shift to the left. GFDL has performed well with this storm relative to other model guidance, but the trough over the midwestern US is very deep and strong and should have no problem steering Ernesto northeastward initially. As a precaution, I will compromise some with GFDL and remain west of the main envelope. By the end of the forecast period when Ernesto reaches the mid-Atlantic, however, the global models show the trough having exited the area, leaving ridging to build in north of Ernesto, and stalling the storm. The forecast is significantly slower after 96 hours and will show a northward track until more is known about the future track.
INIT 22.0N 77.3W 35KTS...EMERGING OVER WATER
12HR 23.0N 78.9W 40KTS
24HR 25.0N 81.0W 50KTS...OVER FLORIDA BAY
36HR 26.5N 81.4W 45KTS...INLAND
48HR 28.9N 81.2W 40KTS...INLAND
72HR 34.8N 78.2W 60KTS...INLAND OVER NC
96HR 36.5N 77.0W 25KTS...INLAND NEAR NC/VA BORDER
120HR 39.0N 77.0W 25KTS...INLAND NEAR WASHINGTON, DC
statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
Ernesto is looking pretty rough this afternoon as the center of circulation has impacted a second round of mountains, this time over extreme eastern Cuba. To its advantage, it is moving farther north than west, so it should emerge over water in the next few hours. How much circulation remains at the low level when Ernesto hits water will greatly affect how strong Ernesto will become. The depression is clearly lacking moisture as convection near the center has greatly diminished, but this too will pick back up over water. The forecast brings Ernesto over water at 30kts this afternoon, and the depression will enter a low shear environment to the southeast of a very large anticyclone over the eastern US. A small upper level low that has lingered in the southwestern Atlantic for a couple days has caused much of the trouble tracking Ernesto and continues to influence the storm northward; however, water vapor images show that the low has been weakening, and model guidance agrees. This would allow Ernesto to bend a little more westward; however, within 36 hours or less, the anticyclone will continue moving southeastward in response to a deep trough over the Midwestern US, and this would pull Ernesto northward. The current motion is already to the right of model guidance, and GFDL and AVN--the two models which actually did indicate such a northward track in the first place are on the east side of model guidance. Ernesto will have plenty of warm water flowing out of the Gulf of Mexico to deal with, and assuming the circulation remains intact this afternoon, Ernesto could become a hurricane. The track is on the right side of guidance as the extrapolated motion is already farther east. This is near the GFDL and AVN solutions in the short term. GFDL branches to the left after 72 hours, and has brought GUNA too far east late. Still, forecast confidence is low.
statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
Ernesto is certainly struggling this evening as its small, compact center has interacted with mountainous terrain of the southwestern Haitian peninsula. Banding features seem to have broken down--microwave shows an ill-organized core. RECON has not found winds above 40kts, and a better intensity estimate may be 35kts, but I will start at 40kts. Cloud tops have intermittently warmed and cooled, and most convection is to the northeast of the center. Southwesterly flow has impacted Ernesto through the day, and land interaction further killed the circulation. Mid-level shear has alleviated some this afternoon, however, and as the center emerges over water between Haiti and Cuba, it should re-intensify some. Within the next day, the center must begin crossing mountainous terrain of eastern Cuba, and this further complicates the intensity forecast. Depending on the angle that Ernesto approaches and crosses Cuba, it could take 12 to 36 hours to emerge back over open water. The current motion and where the center may strengthen relative to its currently estimated position may also have a big impact. SHIPS decay weakens Ernesto to a tropical depression--which it may be close to already, and the future strength of the storm appears bleak. The track forecast is shifted a touch to the left to accommodate a slight westward component due to a large eastern US ridge which may have been underestimated in the previous forecast. This also agrees with model concensus and very near the 00Z CONU. Some part of the circulation will likely remain after it crosses Cuba, and Ernesto should be able to strengthen then. Ernesto may have up to 36 hours over water before making landfall in Florida, and I bring the storm to before landfall.
statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
The cloud pattern on Ernesto is not impressive, but SSD objective intensity estimates are 4.0, or 65kts. RECON reported that pressure rose 5mb in the last few hours to 1002mb, but Ernesto is in a lower pressure environment. Then, a vortex message measured 1007mb. Banding features are very clear on satellite; however, the appearance is a little more ragged. I think that Ernesto is not yet interacting with the southwestern tip of Haiti, but may be simultaneously trying to reform its small ragged eye in an attempt at a rapid intensification cycle. This is a very unusual situation because the eye would still be very small when land interaction occurred, and an ERC may be occurring. It appears that shear has impacted the storm from the northwest; but shear analysis shows low vertical shear and light southwesterly flow associated with an anticyclone at the upper levels. The problem is at the mid-levels; shear from the southwest up to 20kts continues to impact Ernesto. However, I do not see any indication of outflow being cut off ahead of the center. Recently, there has been a convective burst near the center. Possibly, when the primary core of Ernesto broke down during an ERC, mid-level shear impacted the storm. This is likely not a sign of rapid weakening; however, Ernesto will probably have trouble as it interacts with southwestern Haiti. For continuity, winds are kept at 65kts; although, I doubt that 65kt winds are present anywhere. On a positive side though, RECON did report banding evident on radar, indicative of the center holding together. The reason for the lower wind readings is probably that the highest winds are confined to a very small area.
The remainder of the intensity forecast is largely dependent on the next 12 hours and then land interaction. Ernesto has been constantly slipping north of the forecast track, and model guidance has shifted dramatically to the right overnight. Initial motion is unclear since the center is tough to locate, but I am estimating 315/8. Based on current motion, I will have to go to the right of CONU and through eastern Cuba and very near the Florida Peninsula. The mountainous terrain, however, will significantly weaken Ernesto. Obviously, troughing is still strong enough in the southwestern Atlantic to prevent ridging from pushing Ernesto farther west than north. A shallower storm will move northward into troughing, and the intensity forecast is much more conservative, and does not allow Ernesto to strengthen to any more than a Category 1 hurricane--again this is largely dependent on track. The shallow and medium BAM suites are on the right side of the envelope with NOGAPS and AVN, while the deep BAM joins the aggressive GFDL on the left side. The track is a compromise, bringing the center into southern Florida and recurving it for a new trough entering in about 72 hours. Currently, the eastern half of the US is dominated by a very large anticyclone which will slow the storm down and bend the track a little westward before the trough influences it. I am not quick to accelerate Ernesto northeastward yet since the forecast is very uncertain beyond 72 hours.
statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
Earlier this afternoon, the center of circulation appeared to begin becoming exposed from westerly shear; however, since, convection has reformed over the center. Vertical shear ahead of Ernesto is weakened, and is now down to 30kts maximum as opposed to 50kts. An upper level low is currently near the Cayman Islands and retrograding. As this low weakens, shear should subsequently weaken and allow Ernesto to strengthen. SHIPS brings to nearly Category 3 status in 72 hours. After shear decreases in the western Caribbean, the only thing that may cause weakening is land interaction if the storm moves farther north than forecast and later shallower warm waters in the Gulf of Mexico and potential shear later in the forecast period as the storm approaches the coast and enters mid-latitude influence. Shear, however, has not been a problem for many storms in this situation, and on a side note, SHIPS maintains 96kts at 120 hours. The forecast allows for a Category 3 hurricane by the end of the forecast period, and it is possible that Ernesto could intensify more than indicated.
The track forecast is fairly simple; however, the exact timing and bearing of the turn northwestward is unsure as of now. It does appear likely that Ernesto will impact the US Gulf Coast, but anyone in this region should maintain a close watch on the storm over the next few days. The CONU ensemble members are fairly clustered at 12Z, with GFDL taking too much northward turn very early. Still, the globals agree on some amount of turning to the north, and the forecast is adjusted to the right in the later time periods. A mid-latitude trough will move over the continental US through early next week, and while Ernesto will move west-northwestward into a weakness in subtropical ridging caused by the Caribbean upper level low, it will continue northwestward and eventually northward around the west side of the ridge as troughing weakens the ridging. However, at 18Z, AVN has an unreasonable sudden turn to the north in 24 hours, shifting the CONU to the east and showing a curve northeastward. UKMET is farther west, and excluding AVN, the ensemble appears more reasonable. Historically, UKMET tends to perform the best in predicting the path of a storm into the Gulf of Mexico when influenced by mid-latitude features.
Tropical Storm Ernesto Forecast 3
1:30AM EDT SAT AUG 26 2006
...Ernesto strengthens some while moving west-northwestward...
Although these forecasts appear statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
Satellite imagery shows that Ernesto has gained convection and banding features this evening. Intensity is bumped to 40kts for this forecast. The upper level low in the northwestern Caribbean has begun retrograding, and although westerly shear continues to impact the storm, this shear is predicted by some model guidance to decrease, and now appears more likely since the upper level feature has begun moving. The intensity forecast is aggressive, bringing Ernesto to Category 3 status by the end of the forecast period. The track forecast is unchanged from the previous forecast as reasoning remains the same and the storm is currently on track. I have shown a northward shift later in the forecast period to slide closer to the latest CONU.
A more in depth forecast and analysis will be provided later Saturday.
statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
Visible satellite imagery this morning shows that the center of circulation remains on the western side of convection due to westerly shear throughout the Caribbean Sea. However, convection has flared up significantly overnight, and satellite intensity estimates are at 35kts at minimum. The center of circulation is embedded within the circulation; although, microwave shows more convection on the east side of the center with some rough banding. As such, initial intensity is set at 35kts. I will note that I am not very concerned about drier air surrounding the storm to the west; there is apparently at least some moisture in the mid-levels via water vapor imagery; and SSMI shows no lower than 40mm immediately ahead. The main wildcard in this intensity forecast is how the system will respond to shear, and the motion and eventual fate of the trough and upper low over the northwestern Caribbean. This is not a very strong feature, and it appears that the trough will be cut off into a weak shortwave not attached to an ULL at 30N 50W. Still, I cannot be sure until we see the Caribbean ULL be cut off from a larger mid-latitude feature so that ridging can build westward, and troughing would retrograde, allowing the storm to intensify. Global models are apparently not too aggressive yet, indicating that shear will inhibit the storm, and keeping CONU on the south side of model guidance. SHIPS still brings it to 87kts in 120 hours, and I will not go quite this strong, but will forecast a Category 2 hurricane. The track forecast is fairly straight forward. The storm will move west-northwestward into a trough weakness in western Atlantic ridging. If this ULL weakens as forecast, ridging would build back in and allow for more westward component to the motion. This solution is supported by a few of the dynamic models. The track forecast represents this by a slight curve in the track since the uncertainty is greater 4 to 5 days out. This track is also north of the new CONU concensus since the forecast is for a stronger system.
statistically reliable, always first consult and consider official products released by the National Hurricane Center. This forecast is not associated with any other professional or non-professional source of information except nencweather.com
...Tropical wave in eastern Caribbean develops into a tropical depression...
This afternoon, RECON found a closed circulation associated with the tropical wave in the eastern Caribbean, meriting its classification as a tropical depression. Brand new QuikSCAT missed most of the depression, but does show a 25kt vector to the west of the center, and SSD estimates are 30kts. Initial intensity is 30kts. Convection has flared up this evening over the center; however, I don't have any fresh microwave imagery to check out the banding further. Based on infrared satellite it appears that the system has plenty of organization left to take place in that aspect. Additionally, easterly shear is impacting the depression, and vertical shear only increases to the west of the cyclone, and a boundary of convection on the western edge of the storm falls off abruptly into drier air. Apparently though, tropical guidance suggests a drop in shear as SHIPS brings the system to 93kts in 120 hours as it enters the Gulf of Mexico, and the usually overaggressive GFDL brings it to 105kts. Otherwise, the dynamic models have had trouble early with the depression but should pick up on it in the next couple of runs. GFS does pick up on the depression some, and the upper level low and trough over the West-Central Caribbean/SW Atlantic is forecasted to retrograde and weaken later. This would cause shear to lessen, and we have seen several storms intensify last year with dry air in front of them, and the depression is only gaining convection now instead. As such, I am fairly aggressive with intensity, but not as aggressive as model guidance yet until I see the upper level low show signs of retrograding.
Track reasoning is rather simple. Currently, the depression is guidance by ridging over the southwestern Atlantic, and as the shortwave weakens ridging, a slight northward component is expected, perhaps with some more westward component toward the end of the forecast period if ridging is able to build back. I am reluctant to go too strong with intensity until shear lessens, so I am tempted to keep the track on the southern end of model guidance to compromise with the conservative global models. For the meanwhile, mid and low-level shear is weak enough to permit development of the storm. Since I am forecasting a hurricane by the end of the forecast period, I will sit in the center of the guidance envelope for now.
