yoda

Mesoscale Discussion 1673 NWS Storm Prediction Center Norman OK 0206 PM CDT Thu Sep 03 2020 Areas affected...the Mid-Atlantic Concerning...Severe potential...Tornado Watch likely Valid 031906Z - 032100Z Probability of Watch Issuance...95 percent SUMMARY...A tornado watch will be needed this afternoon as a damaging wind and tornado threat increases. DISCUSSION...A broad area of shower activity extends from the Ohio Valley into Pennsylvania and New York amid a belt of strong mid-level flow. Areas south and east of this activity have slowly destabilized through the day with temperatures now in the upper 80s to low 90s in northern Virginia, eastern Maryland, and Delaware. In addition, the boundary layer is very moist with dewpoints in the mid to upper 70s. This has yielded moderate MLCAPE ranging from 1000 to 2000 J/kg across the region despite very weak mid-level lapse rates (5 C/km per 18Z IAD RAOB). Expect at least a few strong storms to develop in the eastern periphery of the cloud shield in the next 1-2 hours as destabilization continues and deep-layer ascent increases ahead of a shortwave moving out of West Virginia. Once storms develop, they will likely become supercellular, at least initially, given 40-45 kts of effective shear (per KLWX VWP and 18Z IAD RAOB). 18Z IAD RAOB showed relatively weak flow in the lowest 1.5 km, but upstream VWP from KRLX shows strong (40 kt) flow at 1km. Once this overspreads northern Virginia, Maryland, and Pennsylvania in a few hours, the damaging wind threat will increase and low-level shear will increase which should increase the tornado threat. The best tornado threat will likely be across northern Virginia, southern Maryland, and far southern Pennsylvania where there has been less mixing and surface winds remain southerly or south-southeasterly. A tornado watch will likely be needed in the next hour or two as storm coverage/intensity increases. ..Bentley/Grams.. 09/03/2020 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...CTP...LWX...RNK...PBZ...RLX...

MCD issued... tornado watch likely... 95 percent

Kind of surprised no MCD yet from SPC

Ugh it's hot and humid out... we better get some storms this afternoon

On your marks... Tropical Weather Outlook NWS National Hurricane Center Miami FL 200 AM EDT Thu Sep 3 2020 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on recently upgraded Hurricane Nana, approaching the coast of Belize, and on Tropical Depression Omar, located a few hundred miles north of Bermuda. 1. A broad area of low pressure located over the eastern tropical Atlantic several hundred miles west-southwest of the Cabo Verde Islands continues to produce a small area of showers and thunderstorms. This system is expected to interact with a tropical wave approaching from the east over the weekend, and it is unclear if the interaction will enhance or inhibit development of this system while it meanders over the eastern and central tropical Atlantic through early next week. * Formation chance through 48 hours...low...20 percent. * Formation chance through 5 days...low...30 percent. 2. A tropical wave located off the coast of west Africa is merging with another disturbance located a couple of hundred miles south of the Cabo Verde Islands, resulting in an extensive area of disorganized showers and thunderstorms. Development of this system is likely to be slow during the next couple of days while it moves west- northwestward at about 15 mph, and a tropical depression is more likely to form early next week over the central tropical Atlantic where environmental conditions are forecast to be more favorable for development. * Formation chance through 48 hours...low...20 percent. * Formation chance through 5 days...high...70 percent. 3. Another tropical wave is forecast to move off the west coast of Africa over the weekend. An area of low pressure is expected to form from the wave, and some development of this low will be possible early next week while it moves generally westward over the far eastern tropical Atlantic. * Formation chance through 48 hours...low...near 0 percent. * Formation chance through 5 days...low...20 percent. Forecaster Berg

I wouldn't say busted looking at the reports https://www.spc.noaa.gov/exper/archive/event.php?date=20120601

New day 1 is out.... 0600 OTLK is ENH risk with 10 TOR/5 HAIL/30 WIND

June 4th and June 10th and June 16th 2008 were MOD risks... but for wind down here

I believe this is the last event that had hatched tor probs in the LWX CWA https://www.spc.noaa.gov/exper/archive/event.php?date=20160224

Evening AFD LWX disco update for tomorrow

Those were at KIAD... KDCA and KEZF look a bit more nasty... along with KBWI too ETA: especially that sounding at KBWI at 00z Friday

Again with the no sprinkler

Those are some nasty soundings on the 00z NAM from 18z THURS to 03z FRI

Are we going to use this thread for both days? Or should we risk getting denied by posting a separate thread lol

Tornado watch coming shortly

Tropical Storm Nana Discussion Number 5 NWS National Hurricane Center Miami FL AL162020 500 AM EDT Wed Sep 02 2020 Nana's Central Dense Overcast has become a little better defined, with cloud tops to -80 deg C or colder. Upper-level outflow continues to be somewhat inhibited over the northern portion of the circulation. SFMR-observed surface winds and adjusted flight-level winds from an Air Force Hurricane Hunter aircraft indicated an intensity of 50 kt. Although northerly shear is likely to limit intensification, the environment is conducive enough for Nana to strengthen into a hurricane later today. The official intensity forecast is close to the Decay-SHIPS prediction based on the ECMWF global model forecast fields. Center fixes from the aircraft indicate that the motion continues to be generally westward, or 270/16 kt, to the south of a strong mid-level high pressure area. Over the next couple of days, the ridge is expected to be maintained or to build a little more to the west. This should keep Nana on a westward or slightly south-of-west track until it moves into Central America. The official track forecast is close to the previous one and also very close to the latest Florida State University Superensemble prediction. Observations from the aircraft and NOAA data buoy 42057 indicate that Nana is a rather small tropical cyclone, with tropical-storm-force winds extending 60 n mi or less from the center. KEY MESSAGES: 1. Tropical Storm Nana is forecast to be a hurricane as it approaches the coast, and interests in Honduras, Guatemala, Belize, and the Yucatan Peninsula should closely monitor the progress of this storm. Strong winds, dangerous storm surge and very heavy rainfall causing flash flooding are becoming more likely from Nana. FORECAST POSITIONS AND MAX WINDS INIT 02/0900Z 17.0N 82.7W 50 KT 60 MPH 12H 02/1800Z 16.9N 85.0W 60 KT 70 MPH 24H 03/0600Z 16.8N 87.6W 65 KT 75 MPH 36H 03/1800Z 16.5N 89.8W 50 KT 60 MPH...INLAND 48H 04/0600Z 16.4N 92.1W 30 KT 35 MPH...INLAND 60H 04/1800Z 16.1N 93.9W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 05/0600Z...DISSIPATED $$ Forecaster Pasch

BULLETIN Tropical Storm Nana Advisory Number 5 NWS National Hurricane Center Miami FL AL162020 500 AM EDT Wed Sep 02 2020 ...NANA CONTINUES WESTWARD... ...LIKELY TO BECOME A HURRICANE BY TONIGHT... SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...17.0N 82.7W ABOUT 210 MI...335 KM ENE OF LIMON HONDURAS ABOUT 365 MI...585 KM E OF BELIZE CITY MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...W OR 270 DEGREES AT 18 MPH...30 KM/H MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

LWX goes big for today and tomorrow in their morning AFD

BULLETIN Tropical Storm Nana Intermediate Advisory Number 4A NWS National Hurricane Center Miami FL AL162020 200 AM EDT Wed Sep 02 2020 ...NANA EXPECTED TO BECOME A HURRICANE BY TONIGHT... SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...17.0N 81.8W ABOUT 265 MI...425 KM ENE OF LIMON HONDURAS ABOUT 425 MI...680 KM E OF BELIZE CITY MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...W OR 270 DEGREES AT 18 MPH...30 KM/H MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES

SPC doesn't like today for us... but tomorrow... woah at the disco... here is the morning Day 2

this weekend looks good for that

00z NAM soundings for both tomorrow and Thursday look pretty nice... Thursday looks a lil better IMO due to a bit stronger deep layer shear

Gone in 72 hours lol Tropical Storm Nana Discussion Number 4 NWS National Hurricane Center Miami FL AL162020 1100 PM EDT Tue Sep 01 2020 Deep convection redeveloped over the center of Nana during the late afternoon and recent microwave imagery has revealed a small, well-defined low-level eye-like feature, and convective banding around the southwestern portion of the circulation. An Air Force Reserve hurricane hunter aircraft that has provided a couple of center fixes within the past hour or two has measured a peak 850-mb flight-level wind of 62 kt, and believable SFMR winds of around 50 kt, which supports an initial intensity of 50 kt. Data from aircraft indicated that the minimum pressure is around 999 mb. Nana is moving westward or 275/16 kt. A strong deep-layer ridge to the north of the tropical cyclone should steer it westward over the next day or so. After that time, the ridge is forecast to build west-southwestward and the dynamical models indicate that this will cause Nana to turn west-southwestward by Thursday. On this track, Nana is expected to approach the coast of Belize late Wednesday night or early Thursday, and move inland over Belize and Guatemala later that day. The track guidance is in good agreement on this scenario but has trended slightly southward, which seems reasonable given that Nana is vertically deep and is more likely to feel the deep-layered east-northeasterly flow. The new NHC track forecast is close to the FSU Superensemble and the HFIP corrected consensus model. The tropical storm is currently within an environment of light to moderate northeasterly shear. This shear does not seem to be strong enough to prevent strengthening during the next 12-24 hours, and the NHC intensity forecast shows a slightly faster rate of intensification during that time. This is in agreement with the latest SHIPS model output and the HCCA and HWRF models, and calls for Nana to become a hurricane within 24 hours. The shear is forecast to become more northerly just before landfall, and this is likely to slow the intensification process. Rapid weakening is expected after landfall, and the low-level circulation is expected to dissipate over Guatemala or southeastern Mexico by day 3. KEY MESSAGES: 1. Tropical Storm Nana is forecast to be a hurricane as it approaches the coast, and interests in Honduras, Guatemala, Belize, and Yucatan should closely monitor the progress of this storm. Strong winds, dangerous storm surge and very heavy rainfall causing flash flooding are becoming more likely from Nana. FORECAST POSITIONS AND MAX WINDS INIT 02/0300Z 17.0N 80.9W 50 KT 60 MPH 12H 02/1200Z 17.1N 83.5W 60 KT 70 MPH 24H 03/0000Z 17.0N 86.3W 65 KT 75 MPH 36H 03/1200Z 16.8N 88.6W 65 KT 75 MPH...INLAND 48H 04/0000Z 16.5N 90.7W 35 KT 40 MPH...INLAND 60H 04/1200Z 16.2N 93.1W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 05/0000Z...DISSIPATED

8pm TWO mentions 30 percent chance for that to develop 1. Showers and thunderstorms associated with a small area of low pressure about midway between the Windward Islands and west Africa appear to be slowly becoming better organized. Some additional development of this system is possible this week as the system meanders in the central tropical Atlantic Ocean. * Formation chance through 48 hours...low...20 percent. * Formation chance through 5 days...low...30 percent.

URNT12 KNHC 011719 VORTEX DATA MESSAGE AL162020 A. 01/16:32:20Z B. 16.59 deg N 077.82 deg W C. 850 mb 1455 m D. 1004 mb E. 290 deg 15 kt F. CLOSED G. C6 H. 42 kt I. 119 deg 10 nm 16:24:00Z J. 076 deg 58 kt K. 343 deg 6 nm 16:30:30Z L. 48 kt M. 295 deg 34 nm 16:47:00Z N. 052 deg 54 kt O. 316 deg 7 nm 16:39:30Z P. 17 C / 1522 m Q. 20 C / 1540 m R. 14 C / NA S. 12345 / 8 T. 0.02 / 1.25 nm U. AF307 01FFA INVEST OB 16 MAX FL WIND 60 KT 078 / 7 NM 15:39:30Z ;