WxWatcher007

To amplify the point ^

Excellent discussion tonight. Still a ton of uncertainty with this. Tropical Storm Elsa Discussion Number 6 NWS National Hurricane Center Miami FL AL052021 1100 PM AST Thu Jul 01 2021 The convective structure with Elsa tonight appears to be somewhat better organized than earlier, with a bursting type pattern of cold -75 to -80 C cloud top temperatures just to the northeast of the estimated center. However, a SSMIS microwave pass at 2130 UTC revealed that, underneath the cirrus, the deeper convection is still struggling to rotate up-shear as the system moves quickly to the west-northwest. Despite that fact, an ASCAT-A pass clipped the northeastern edge of Elsa and showed several wind retrievals of 44-46 kt. In addition, the most recent subjective Dvorak satellite classification from TAFB was T3.0/45 kt. In support of these data, the current estimated intensity was raised to 45 kt for this advisory. Elsa continues to move quickly to the west-northwest at 290/23 kt. A continued rapid motion to the west-northwest is expected for the next 36 hours as the storm remains steered by a strong subtropical ridge to its north, and the guidance has trended a bit faster once again tonight. Thereafter, Elsa will reach the western extent of this ridge which will be eroded by a strong mid-latitude trough centered off the eastern US. Once again, the guidance spread increases greatly by this time, with the GFS/UKMET on the slow and left side of the guidance envelope, the ECMWF and its ensembles on the fast and right side, and the Canadian roughly in the middle. Interestingly, the latest GFS ensembles show some bifurcation within the larger guidance envelope, with the strongest members further south and west. The latest NHC track forecast is close to the previous track early on but somewhat faster, and in the latter period was nudged just slightly eastward towards the TVCN consensus. However, the track forecast in the latter time period remains low confidence. The intensity forecast with Elsa also continues to be challenging this evening. While the GFS-based SHIPS guidance indicates that the current 200-850-hPa vertical wind shear is only 5-10 kt, the strong east-southeasterly low-level flow Elsa is embedded in is resulting in stronger 15-20 kt of west-northwesterly mid-level shear. This mid-level shear has thus far prevented deep convection from wrapping around the circulation and helping to align the low- and mid-level vortex like the GFS/HWRF models have been forecasting over the past day. Despite this convective structure, the fast east-southeasterly low-level flow will likely continue to enhance the winds on the north side of the circulation. For this reason, the intensity forecast still shows intensification in the short term to 55 kt. However, additional intensification beyond that will likely require a better vertically aligned vortex. This structure may be difficult to achieve as moderate mid-level shear continues, counter to the motion vector of the storm. After 48 hours, the intensity forecast shows slight weakening given the possibility of land interaction over the Greater Antilles. The latest intensity forecast continues remain on the conservative side relative to the guidance, especially the HWRF/HMON regional hurricane models, and is also low confidence. Key Messages: 1. Tropical storm conditions are expected to begin early Friday in portions of the Windward and southern Leeward Islands, and are possible over portions of southern Hispaniola on Saturday, and are also possible over Jamaica beginning Saturday night. 2. Heavy rainfall from Elsa will move quickly across the Windward and southern Leeward Islands, including Barbados, on Friday. Outer rain bands will impact Puerto Rico on Friday and southern Hispaniola by early Saturday. Flooding and mudslides are possible. 3. There is a risk of wind and rainfall impacts in portions of Cuba, the Turks and Caicos, and the Bahamas through early next week. Interests in these areas should monitor Elsa's progress and updates to the forecast. 4. There is a risk of storm surge, wind, and rainfall impacts in the Florida Keys and portions of the Florida Peninsula early next week. However, the forecast uncertainty remains larger than usual due to Elsa's potential interaction with the Greater Antilles this weekend. Interests in Florida should monitor Elsa's progress and updates to the forecast. FORECAST POSITIONS AND MAX WINDS INIT 02/0300Z 11.8N 55.9W 45 KT 50 MPH 12H 02/1200Z 12.8N 59.7W 55 KT 65 MPH 24H 03/0000Z 14.5N 64.8W 55 KT 65 MPH 36H 03/1200Z 16.2N 69.8W 55 KT 65 MPH 48H 04/0000Z 17.7N 73.3W 55 KT 65 MPH 60H 04/1200Z 19.4N 76.5W 50 KT 60 MPH 72H 05/0000Z 21.2N 78.8W 50 KT 60 MPH 96H 06/0000Z 23.9N 81.7W 50 KT 60 MPH 120H 07/0000Z 28.2N 83.1W 50 KT 60 MPH $$ Forecaster Papin/Brown

It looks quite good tonight on IR. It needs to keep the deep convection going for like 12-24 hours though to really allow for an inner core to develop. We see plenty of systems look good overnight just to have the convective trend collapse after losing the diurnal assist. Heck of a start tonight though with those hot towers.

Wow. Looks like tropical…

Just ripping here. Love it.

Even better look now. Can’t wait for recon to start running because IR can definitely be deceiving. Great convective burst regardless tonight.

Absolutely pouring right now.

Severe Weather Statement National Weather Service Baltimore MD/Washington DC 902 PM EDT Thu Jul 1 2021 DCC001-MDC033-VAC013-510-020130- /O.CON.KLWX.TO.W.0016.000000T0000Z-210702T0130Z/ District of Columbia DC-Prince Georges MD-Arlington VA- City of Alexandria VA- 902 PM EDT Thu Jul 1 2021 ...A TORNADO WARNING REMAINS IN EFFECT UNTIL 930 PM EDT FOR THE SOUTHERN DISTRICT OF COLUMBIA...WEST CENTRAL PRINCE GEORGES...AND SOUTHEASTERN ARLINGTON COUNTIES AND THE NORTHEASTERN CITY OF ALEXANDRIA... At 902 PM EDT, a severe thunderstorm capable of producing a tornado was located over Rosslyn, moving east at 35 mph. HAZARD...Tornado. SOURCE...Radar indicated rotation. IMPACT...For those in the direct path of a tornado touchdown, flying debris will be dangerous to those caught without shelter. Damage to roofs, siding, and windows may occur. Mobile homes may be damaged or destroyed. Tree damage is likely. This dangerous storm will be near... Crystal City and Reagan National Airport around 905 PM EDT. Nationals Park, RFK Stadium, Gallaudet University, Anacostia and US Capitol around 910 PM EDT. Oxon Hill and Marlow Heights around 915 PM EDT. Coral Hills, Camp Springs, Walker Mill, Temple Hills, Seat Pleasant and Carmody Hills-Pepper Mill Village around 920 PM EDT. Other locations impacted by this tornadic thunderstorm include Rock Creek, Capitol Heights, Bolling Air Force, Suitland-Silver Hill, The White House, The Mall, Fairmount Heights and District Heights. PRECAUTIONARY/PREPAREDNESS ACTIONS... TAKE COVER NOW! Move to a basement or an interior room on the lowest floor of a sturdy building. Avoid windows. If you are outdoors or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris. && LAT...LON 3886 7710 3891 7709 3890 7687 3879 7693 TIME...MOT...LOC 0102Z 285DEG 28KT 3889 7707 TORNADO...RADAR INDICATED HAIL...0.00IN

Big time signature

Note there’s also a flight scheduled for 12z tomorrow not listed here.

Gust to 65 in Annapolis per TWC

Down 1mb at 2pm FWIW. Not much

Just outrageous forward motion @Windspeed. Practically supersonic. That’s a way to get from the central Atlantic to Tampa in 5 days

Definitely has a chance to struggle, but kind of like like Tip said, as long as there’s convection near the center, it’s more likely to be resilient. All it takes is one burst to breathe new life into it so to speak. I think everything from Pensacola to OTS ~100-150 miles off the coast is still on the table. SE US shouldn’t take their eyes off this one yet IMO. It’s always more lottery odds up here for impacts, as you know. I think I have a sense of the most likely general evolution, but this isn’t an easy forecast.

For those of you wondering what to watch for today. Forward motion of 25kts is SCREAMING fast.

Almost as mythical as our annual up the bay run

This latest GFS run is ugly for the west coast of Florida.

IMO, the steering pattern actually looked ripe for a close US approach a week ago. If you look at the 500mb look on both the EPS and GEFS, they're pretty similar. A strong subtropical ridge developed and has been in place to steer whatever was to develop in the MDR to the west, which is happening now. We also know that our crappy holiday weekend trough comes in creates a weakness that almost certainly turns what we now know to be Elsa. The devil is in the details though. Timing/placement/strength of the ridge and trough determines when the slow down and turn happens, as well as the sharpness of the turn. We also have to watch for center reformations with this as it is still a bit decoupled and moving at a ridiculous pace to the WNW. I'm not all the way in the GFS camp, but frankly, I think the Euro/EPS is too weak and too quick to shunt Elsa NW and then NE. I really like the NHC track right now and perhaps a more gradual turn NE in the wake of the trough that allows Elsa to scrape the SE coast and head OTS south of here. That's just speculation though at this range. I know you didn't ask this, but one thing to be considered is what happens if it misses Haiti/DR in favor of a more westward track. The NHC is admittedly conservative with their forecast (also signaling they're tossing the Euro for now) and that makes sense. A further west track would not only place Elsa in the best thermal environment in the basin, it'd coincide with a slowdown over those waters and reduction in shear as the system reaches the periphery of the ridge and sees less influence from trade winds. For something coming relatively quickly, this is a highly uncertain forecast. This one has some legit potential though if it can get far enough west without land interaction.

Since I start 98% of the tropical threads on AmWx I figured it was time to start this one. Last year we had TS Fay landfall to the south of the region, essentially a direct hit by TS Isaias, and a relatively close approach by the post tropical remnants of Hurricane Teddy. Most of the time tropical and New England in the same sentence is akin to snow in Las Vegas. Doesn't mean we can't talk tropical. That said, TS Elsa might be worth a casual eye in the coming days as some operational guidance tries to take it northeastward after a trip through the eastern Caribbean Graveyard. As always, very low probability deal up this way, especially this far out, but it's the first real tropical worth discussing.

I wouldn’t be biting on any longer range intensity or track solution right now. Ensemble guidance is still very wide 4-5 days out. Also current intensity matters a lot less here than it’s inner organization. The more organized it becomes before the Lesser Antilles, the more likely it is to survive the Caribbean IMO, even if that doesn’t translate into wind speed early on.

Tropical Depression Five Discussion Number 2 NWS National Hurricane Center Miami FL AL052021 1100 PM AST Wed Jun 30 2021 The satellite presentation of the system over the last 6-12 hours has continued to gradually improve, with a prominent banding feature to the west of the estimated center. An ASCAT-A pass received at 2323 UTC revealed that the low-level circulation has become a bit better defined compared to earlier today, though still somewhat elongated to the south and west. The peak wind retrievals from this instrument were 30-32 kt. While subjective satellite estimates from TAFB and SAB were a bit higher, the latest estimated intensity was held at 30 kt for this advisory in agreement with the slightly lower scatterometer data. The initial motion has accelerated a bit tonight at 280/20 kt. A strong subtropical ridge is situated poleward of the tropical depression and this feature should steer the system quickly to the west-northwest over the next several days. After 72 hours, the tropical cyclone will reach the westward extent of the ridge and begin to move more poleward and slow down as the ridge also becomes eroded by a mid-latitude trough to over the eastern US. The track guidance in the latter portion of the forecast continues to exhibit large spread, with the GFS and HWRF/HMON models along the left side of the guidance envelop, while the ECMWF and its ensemble mean on the right side. The latest NHC track forecast is a shade right of the previous one, and also slightly faster, but given the spread in the models, the latter portion of the track is more uncertain than usual. While the depression is currently in a favorable environment of low vertical wind shear, warm sea-surface temperatures, and high mid-level relative humidity, the expected acceleration in forward motion could cause the system to outrun the favorable upper-level easterlies currently overhead, after 36 hours. In addition, the system could be near or over some of the Greater Antilles in the latter portions of the forecast. For these reasons, the intensity remained capped at 50 kt after 36 hours, and is still on the lower end of the intensity guidance suite, though this forecast could be somewhat conservative. Key Messages: 1. The tropical depression is expected to become a tropical storm before reaching the Lesser Antilles and tropical storm conditions are expected beginning late Thursday night in portions of the Windward and southern Leeward Islands. 2. Heavy rainfall will move quickly across the Windward and southern Leeward Islands, including Barbados, on Friday. Isolated flash flooding and mudslides are possible. 3. There is a risk of wind and rainfall impacts in portions of the Virgin Islands, Puerto Rico, Hispaniola, Cuba, the Turks and Caicos and the southeastern Bahamas through early next week. Interests in these areas should monitor the system's progress and updates to the forecast. 4. Interests in Florida should monitor updates to the forecast for this system, but it is too soon to determine what if any impacts could occur there next week given the uncertainty in the long-range forecast. FORECAST POSITIONS AND MAX WINDS INIT 01/0300Z 9.6N 46.3W 30 KT 35 MPH 12H 01/1200Z 10.5N 49.6W 40 KT 45 MPH 24H 02/0000Z 11.7N 54.4W 45 KT 50 MPH 36H 02/1200Z 13.0N 59.6W 50 KT 60 MPH 48H 03/0000Z 14.7N 65.0W 50 KT 60 MPH 60H 03/1200Z 16.5N 69.8W 50 KT 60 MPH 72H 04/0000Z 18.3N 73.8W 50 KT 60 MPH...NEAR THE COAST 96H 05/0000Z 20.9N 78.6W 50 KT 60 MPH...NEAR THE COAST 120H 06/0000Z 24.5N 82.0W 50 KT 60 MPH...OVER WATER $$ Forecaster Papin/Brown

The next few days will be telling, as other guidance keeps PTC 5 intact heading into the Gulf while the Euro/EPS kill it and keep whatever destroyed vorticity east of the US. NHC chose the non-euro camp but it can’t be understated how uncertain the longer term future is for this system. If it gets to the western Caribbean it may very well find another favorable window before being turned by the trough.