yoda

I asked them (LWX) on Twitter aka X... will let you know what they say

15z HRRR For 20z-22z... MD gets clipped, but DC/N VA and south get smacked by the overnight MCS at the end of the run

14z HRRR blows up some supercells (I'm assuming thats what they are) across the region around 20z

Don't usually see the bolded rea Forecast Discussion National Weather Service Baltimore MD/Washington DC 1000 AM EDT Fri May 16 2025 .SYNOPSIS... A warm front is expected to lift through and to the northeast of the region today into late afternoon. A low pressure system will move into the Great Lakes today with a trailing cold front pushing through the area on Saturday. High pressure will build in from the north Sunday and Monday. && .NEAR TERM /THROUGH TONIGHT/... As expected, a line of moderate to heavy showers has developed across central MD this morning and is moving east towards the Chesapeake Bay. This is along a boundary set off by a much stronger MCS that is ripping across northern PA at this time. It doesn`t appear that the line will have anything severe over our area, but a brief downpour can be expected in these areas. Later this afternoon into this evening, thunderstorms may develop along remnant outflows from this morning convection in conjunction with Bay/River breezes. This would be our first shot at severe thunderstorms today, and would generally be along and east of I-95 roughly. It seems that we will have no issues with heating today, along with very high dew points in the 70s, so this round could be quite strong if it is able to develop. Model guidance and current obs do depict some westerly mid-level flow, which could be an inhibiting factor to CI this afternoon. However, I want to stress that if something does develop in this environment, all hazards will be possible with any storm that develops. Another round of severe weather could be on the horizon later this evening into the overnight hours. This is still very uncertain though, and very dependent on an MCS developing to our west and tracking in such a way that would impact our area. Since we won`t have our daytime heating, the severity could be diminished some, but the humidity, nearby trough, approaching cold front on Saturday could be enough to make it interesting in terms of severe elements overnight. At this time, would feel more confident that this occurs across central/southern VA, but can`t be 100 percent certain at this time. This is very much a "wait and see what develops" scenario and will be much more in the way of NOWcasting later today. Given all of these threats today, the Storm Prediction Center has our region in a Slight Risk for Severe Thunderstorms today into tonight. The threats are damaging wind gusts and large hail. Accompanying these threats will be heavy rain and could occur over areas that had already taken on a lot of rainfall in the past few days. A marginal risk for excessive rainfall is also highlighted for our area today for the localized potential for some flash flooding. High temperatures today should push the upper 80s in the eastern half or even close to 90.

Watch up URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 260 NWS Storm Prediction Center Norman OK 1005 AM EDT Fri May 16 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Delaware Far Eastern Maryland New Jersey Far Eastern Pennsylvania Coastal Waters * Effective this Friday morning and afternoon from 1005 AM until 500 PM EDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Thunderstorms continue to strengthen as they move into more of eastern PA and eastern MD. Destabilization is expected downstream, with the resulting combination of instability and shear supportive of supercells capable of large hail and damaging gusts. The severe thunderstorm watch area is approximately along and 55 statute miles east and west of a line from 15 miles northwest of Trenton NJ to 45 miles south of Dover DE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0).

Mesoscale Discussion 0808 NWS Storm Prediction Center Norman OK 0846 AM CDT Fri May 16 2025 Areas affected...the Lower Mid-Atlantic States Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 161346Z - 161545Z Probability of Watch Issuance...80 percent SUMMARY...A few supercells could develop before midday across parts of the Lower Mid-Atlantic region. Large hail and damaging winds should be the primary hazards into early afternoon. DISCUSSION...An arcing band of convective development is underway south of a morning MCS across over central/eastern PA. This arc extends southward through central MD towards the DC metro vicinity. 12Z WAL to PIT soundings sampled a favorable environment for supercells with 40-50 kt effective bulk shear, largely driven by speed change with height amid unidirectional west-northwesterlies. This was coupled with moderate mid-level lapse rates of 6.5 to 7 C/km. 12Z HRRR and 00Z HREF guidance have a signal for longer-track 2-5 km UH, with potential for a few supercells. Given the orientation of the convective development, this seems probable across parts of eastern MD, DE, and far southern NJ. Pronounced surface heating in this area, south of persistent cloudiness farther north, will aid in further destabilization and increase the risk for both large hail and damaging winds by midday. ..Grams/Mosier.. 05/16/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...CTP...LWX... LAT...LON 40727641 40517541 39887448 39177448 38267486 38037544 38087591 38427700 38917704 39777645 40277652 40727641 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

Severe Thunderstorm Watch coming shortly for NE MD and DE/Eastern Shore https://www.spc.noaa.gov/products/md/md0808.html

Radarscope says max hail 3.5" Seeing a few 80 dBz pixels

Tornado Watch likely in next hour or two for S WI/ N IL https://www.spc.noaa.gov/products/md/md0791.html Mesoscale Discussion 0791 NWS Storm Prediction Center Norman OK 0214 PM CDT Thu May 15 2025 Areas affected...Parts of southern Wisconsin into northern Illinois Concerning...Severe potential...Tornado Watch likely Valid 151914Z - 152115Z Probability of Watch Issuance...80 percent SUMMARY...A tornado watch will likely be needed this afternoon. Supercells capable of all severe hazards are expected within the next few hours. DISCUSSION...Cumulus continue to deepen both along a dryline and an area of confluence within the Mississippi Valley. Whether storms develop within the confluence or when the dryline reaches the Mississippi River remains a question. 40-50 kts of effective shear across these surface convergence zones will favor supercells as storms develop. Large to very large hail will be a concern as well as severe wind gusts. The 18Z DVN sounding sampled very steep mid-level lapse rates and a long hodograph. Tornado potential will also be present. Surface temperature/dewpoint spreads are near 20 F, but low-level shear and a supercellular mode will favor low-level rotation. The time frame of greater tornado potential will likely be 22-00Z when the low-level jet increases in southern Wisconsin. ..Wendt/Mosier.. 05/15/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRB...LOT...MKX...DVN...ARX... LAT...LON 41418999 41579025 41819042 42309082 42909119 43299134 43549126 44009048 44358993 44438931 43978880 43168862 42128827 41798867 41418999 MOST PROBABLE PEAK TORNADO INTENSITY...120-150 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN

Mention of "some thunderstorms may be severe" in the updated zones for Friday night

Watch coming soon - https://www.spc.noaa.gov/products/md/md0788.html Mesoscale Discussion 0788 NWS Storm Prediction Center Norman OK 0123 PM CDT Thu May 15 2025 Areas affected...portions of eastern West Virginia and much of Virginia Concerning...Severe potential...Watch possible Valid 151823Z - 152000Z Probability of Watch Issuance...60 percent SUMMARY...The severe threat should increase over the next few hours. Multicells and supercells will be the primary storm mode, with severe wind and hail the main threats. A few instances of 2+ inch diameter hail are possible. A Severe Thunderstorm Watch will eventually be needed. DISCUSSION...Satellite imagery shows agitated cumulus along the WV/VA border, driven primarily by boundary layer destabilization, along with orographic lift associated with the Appalachians. Surface temperatures have already warmed into the mid to upper 70s F to the immediate lee of the Appalachians, where upper 60s F dewpoints, beneath the eastward extent of an EML plume, supports 1500+ J/kg MLCAPE. The 17Z RNK observed sounding shows 8 C/km 700-500 mb lapse rates and the freezing level around 600 mb, beneath where most of the CAPE resides, along with modestly elongated hodographs. Such conditions support supercells capable of severe gusts and large hail, including a few instances of 2+ inch in diameter stones. Given a gradually increasing severe threat, a Severe Thunderstorm Watch will eventually be needed. ..Squitieri/Mosier.. 05/15/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...LWX...RNK...RLX... LAT...LON 36608017 36768076 37298113 37938092 38388044 38797971 38967837 38617777 37937732 37257730 36797770 36637848 36608017 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1220 PM CDT Thu May 15 2025 Valid 161200Z - 171200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHEAST MISSOURI...SOUTHERN ILLINOIS/INDIANA...AND CENTRAL AND WESTERN KENTUCKY... ...SUMMARY... A regional outbreak of severe thunderstorms is likely across parts of the middle Mississippi and Ohio Valleys Friday afternoon into Friday night. This may include a few intense supercells posing a risk for large hail and tornadoes. During the evening into the overnight hours, this will include an upscale growing and organizing bowing line of storms posing a risk for strong, damaging winds and a continuing risk for tornadoes. ...A regional outbreak of severe storms is expected on Friday across portions of the Mid-South to the Ohio Valley... ...Synopsis... An upper cyclone over the Upper Midwest and attendant shortwave trough will develop east/northeast across much of the Midwest and TN Valley. A swath of strong mid/upper southwesterly flow will accompany this system. Forecast guidance shows a 70-90 kt 500 mb jet spreading across the Mid-MS to OH Valley, while 850-700 mb increases to 40-60 kt by midday. This will result in supercell wind profiles, support widespread organized convection. Favorable deep-layer shear will extend downstream into the central Appalachians and Mid-Atlantic vicinity as well. At the surface, low pressure will shift east from northern MN into the Upper Great Lakes. A warm from southern MO into the OH Valley Friday morning is forecast to lift northward through the afternoon, allowing rich boundary layer moisture (mid/upper 60s F dewpoints) to overspread much of the Lower OH Valley, with a large warm sector in place across a broad region from east TX to the Great Lakes and eastward toward the Mid-Atlantic coast. Corridors of moderate to strong destabilization during the day and into the nighttime hours will support several areas of severe storms from east Texas into much of the Midwest and the Mid-Atlantic, some of which could be significant. ... ...Central Appalachians to Mid-Atlantic... Thunderstorms may be ongoing Friday morning across parts of PA and spread east/southeast through early afternoon as a lead upper shortwave impulse moves across the Northeast. Moistening and heating ahead of this activity will support moderate to strong destabilization, especially from the Chesapeake Bay vicinity southward across the VA/NC Piedmont. The initial round of thunderstorms may pose a risk for locally strong gusts and hail before moving offshore the NJ/DE/MD coast during the early afternoon. During the evening/overnight hours, a mature bowing MCS is expected to move over the WV/VA/NC mountains and spread east across the region, posing a risk for swaths of strong to damaging wind gusts. Forecast guidance varies in timing and exact evolution of this system across the region, but portions of the area may need higher probabilities in subsequent outlooks.

SLGT risk up for the entire LWX CWA for tomorrow on 1730z SPC OTLK. ENH knocking on the door of our western zones

Sounds like Tor Watch coming soon for parts of MN/WI per latest MCD https://www.spc.noaa.gov/products/md/md0786.html

Oh Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CDT Thu May 15 2025 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EAST-CENTRAL MINNESOTA...MUCH OF WISCONSIN...SOUTHERN AND WESTERN LOWER MICHIGAN...NORTHEAST ILLINOIS...NORTHERN INDIANA AND NORTHWEST OHIO... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF VIRGINIA AND NORTHEAST NORTH CAROLINA... ... ...Central Appalachians/Mid-Atlantic... Large-scale height rises are expected across the region, but diurnal heating and orographic effects will aid in thunderstorm development across the higher terrain this afternoon. Northwesterly flow aloft will favor a southeastward storm motion within an environment of moderate/locally strong instability. 35-45 kts of northwesterly deep shear is anticipated, supporting supercell structures and clusters, posing a risk for large hail and damaging winds. The overall hodograph structure and resulting storm motion appears favorable for some very large hail over 2" in diameter as well. ..Mosier.. 05/15/2025

Oh okay then - I know this is more just to the S and W of most of us... But still don't see hatched hail around here very often... @high risk @George BM @Kmlwx @Eskimo Joe

12z NAM Nest soundings suggest nastiness tomorrow evening into nighttime

Which ones?

I know we've mentioned the trigger issue, but damn, that 18z NAM sounding for DC metro at 00z Saturday

https://www.espn.com/nfl/story/_/id/45146544/rb-derrick-henry-agrees-two-year-30m-extension-ravens Congratulations Ravens fans

What do you think of the MCS complex and increasing MLLR/hodographs early Saturday morning the 12z NAM comes up with?

Someone broke the 12z NAM Nest soundings at the end of its run 5000-6000+ SBCAPE because DPs are in the upper 70s

12z NAM continues with the significant hail in the SARS... probably overdone with SBCAPE - suggesting 4000 J/KG... but 21z Friday near DCA is 88/73 Then it really lights up again around 09z SAT... ML Lapse rates are near 8 C/KM and hodos quickly become curved and elongated

Some unheard of values for our region showing up on some of the 00z NAM soundings re SHIP... seeing 2.5 to 3.5 values. Supercell composite lights up quickly Friday afternoon and evening... and lots of significant hail showing up in the SARS, especially some 2" to 4" ones June 9 1990 00z IAD 3.50" is one of them @high risk @Kmlwx @Eskimo Joe

Flash Flood Warning National Weather Service Baltimore MD/Washington DC 935 PM EDT Tue May 13 2025 ...FLASH FLOOD EMERGENCY FOR THE STANARDSVILLE, RUCKERSVILLE, AND DAWSONVILLE AREAS INCLUDING THE HIGHWAY 29 AND 33 CORRIDORS... The National Weather Service in Sterling Virginia has issued a * Flash Flood Warning for... Greene County in central Virginia... * Until 1245 AM EDT. * At 935 PM EDT, emergency management reported thunderstorms producing heavy rain in The Stanardsville, Ruckersville, and Dawsonville areas including the Highway 29 and 33 corridors. Between 3 and 6 inches of rain have fallen. The expected rainfall rate is 1.5 to 2.5 inches in 1 hour. Additional rainfall amounts of 1 to 3 inches are possible in the warned area. Flash flooding is already occurring. This is a FLASH FLOOD EMERGENCY for The Stanardsville, Ruckersville, and Dawsonville areas including the Highway 29 and 33 corridors. This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER GROUND NOW! HAZARD...Life threatening flash flooding. Thunderstorms producing flash flooding. SOURCE...Emergency management reported. IMPACT...This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER GROUND NOW! Life threatening flash flooding of low water crossings, small creeks and streams, urban areas, highways, streets and underpasses. * Some locations that will experience flash flooding include... Stanardsville... Ruckersville... Lydia... Amicus... Mcmullen... Haneytown... Quinque... Saint George... Fletcher... Burtonville... Shady Grove... Newtown... Dawsonville... Mission Home... This includes the following Flood Prone Roads... Mutton Hollow Road near Spotswood Trail, Carpenters Mill Road at Route 607, Advance Mills Road and and Route 617, Westview Road and Deep Step Drive, Seminole Trail at White Run near Route 645, Route 621 along South River near Madison Road, 3300 Block of Spotswood Trail, Garth Road near Swift Run, Dyke Road near Blue Run near Spotswood Trail, South River Road near The South River, Dundee Road at The South River, Middle River Road near The Conway River, Octonia Road at South River Road and Celt Road near Amicus Road. PRECAUTIONARY/PREPAREDNESS ACTIONS... Move to higher ground now! This is an extremely dangerous and life-threatening situation. Do not attempt to travel unless you are fleeing an area subject to flooding or under an evacuation order. Turn around, don`t drown when encountering flooded roads. Most flood deaths occur in vehicles. Be especially cautious at night when it is harder to recognize the dangers of flooding. && LAT...LON 3836 7843 3832 7838 3832 7836 3829 7836 3829 7835 3828 7835 3827 7829 3819 7837 3828 7866 3829 7865 3829 7864 3834 7855 3836 7854 3837 7853 3839 7852 3840 7850 3848 7845 3845 7844 3841 7844 3838 7842 FLASH FLOOD...OBSERVED FLASH FLOOD DAMAGE THREAT...CATASTROPHIC EXPECTED RAINFALL RATE...1.5-2.5 INCHES IN 1 HOURS