yoda

One of the best written AFD from LWX 26 27 28 032 FXUS61 KLWX 302011 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 411 PM EDT Fri May 30 2025 .SYNOPSIS... Low pressure will track through the area this evening, before departing off to our northeast tomorrow. High pressure will build into the area on Sunday, and remain in control over the area through much of the upcoming week. && .NEAR TERM /THROUGH TONIGHT/... Synoptic overview: Current water vapor imagery shows a vigorous upper low centered off to our west over OH/WV. Moisture continues to stream northward into the area at in advance of this disturbance. Further to the west, a prominent mid-level dry slot is wrapping into the system from the southwest, extending from the Tennessee Valley into West Virginia. A broken, disorganized zone of showers is ongoing within the moist advection regime at low to mid levels, and currently extends from the central Virginia Piedmont northwestward to western Maryland. While some intensification of this activity can`t be ruled out, the expectation is for it to remain just showers. Further west, a more intense band of showers and thunderstorms has developed within the mid-level dry slot, and extends northward from southwest Virginia into central West Virginia. This area of storms is expected to intensify further as it tracks eastward into our area later this afternoon into this evening. As we move forward in time, the entire system will continue to gradually translate eastward. In any given location, on and off showers will be possible for a few hours, before a more focused zone of showers and thunderstorms passes through during a 1-2 hour window. Those stronger storms will reach far western portions of the forecast area over the next 1-2 hours, the Blue Ridge by around 5-7 PM, and then the I-95 corridor around 7-10 PM. These storms will produce the greatest threat for severe thunderstorms, and may also result in some isolated instances of flash flooding. Later tonight a surface low associated with the system will start to deepen overhead as it tracks along a frontal boundary which will extend east-northeastward across northern MD and southern PA. As this occurs, a secondary deformation driven area of precipitation will develop on the backside of the low. This may lead to an additional 2-4 hour period of rain later tonight, with embedded moderate to heavy rain. This activity should be strongest in the vicinity of the front across northern Maryland. An overview of various weather hazards follows... Flash Flooding: There has a been a pronounced northwestward trend in the track of the surface low and the resultant axis of anticipated heaviest rainfall over the past 12-24 hours. While there is still a non-zero chance for flooding, the magnitude of the threat for flooding locally appears to be shifting northward and trending downward in magnitude. All locations should experience a brief period of heavy rainfall in association with the thunderstorms in the north- south oriented band currently over West Virginia. Given recent heavy rainfall, it won`t take much to cause flooding issues. 1 hour Flash Flood guidance is actually below one inch across much of the area, and under 1.5 inches over the vast majority of the forecast area. While the trend has been downward in expected rainfall totals, even brief periods of heavy rainfall may lead to isolated instances of flooding as the storms move through. Any supercells could locally enhance rainfall rates beyond what one might expect with PWATs around 1.5 inches. The second round of rainfall later tonight should be most intense across northern Maryland, where the overall threat for flooding will be maximized. Overall, totals are expected to be around 1-3 inches to north of I-70, with localized higher totals in excess of 3 inches. Further south, totals may average less than one inch, but localized higher totals that could cause flash flooding issues may still be possible. A Flood Watch for flash flooding remains in effect for the entire area through tonight. Severe Thunderstorms: Model soundings show an environment characterized by deep moisture, with nearly saturated profiles. MLCAPE is expected to increase to around 1000-1500 J/kg across much of the area over the next few hours. Deep layer shear in also increasing from the south and west, with effective bulk shear anticipated to increase to around 40-60 knots. Low-level shear on the other hand is much weaker, with only around 10-20 knots of southerly flow at 850 hPa. Strong deep layer shear should result in the development of supercells. In terms of individual threats, damaging wind potential may be a bit lower than one might expect with supercells around. DCAPE is very low (around 200-400 J/kg), suggesting that downburst potential is low. Low-level lapse rates aren`t overly impressive either (around 7.5 C/km), and the background low-level wind field is on the weaker side. While a few isolated instances of damaging winds may be possible, it doesn`t appear to be an overly impressive setup for damaging winds. It`s also worth noting that with saturated soils, it likely won`t take much to bring down trees. With supercells around, a few large hail reports can`t be ruled out, but the environment doesn`t appear to be the most favorable for large hail either. Profiles are saturated, a large portion of the CAPE is located below the freezing level, and mid-level lapse rates are poor, each of which work against efficient hail production. The presence of supercells and the strong updrafts they produce would be a favorable aspect for hail production. The tornado threat is a bit more interesting. Moist profiles with low LCLs, a supercellular mode, and ample 0-3 km CAPE (which will lead to efficient stretching and tilting of environmental vorticity) are factors that would favor the development of tornadoes. On the other hand, low level shear and resultant SRH are both on the weaker side, which limits the amount of environmental vorticity present to stretched into the vertical. A few tornadoes appear possible, but at the same time it also doesn`t look like an environment conducive for the development of stronger tornadoes. A Tornado Watch is currently in effect for western portions of the forecast area, and much of the rest of the area remains in a Slight Risk for severe thunderstorms from SPC. Another potential threat worth mentioning is increasing synoptic winds within northwesterly flow on the backside of the low later tonight. Model soundings show around 40-50 knots of flow developing just above the surface. While most of this wind likely won`t make it down to the surface, gusts of 20-30 knots may be possible later tonight, and some localized higher gusts can`t be ruled out.

I think our line we are watching is in WV right now for this evening

Tornado Watch up for i81 corridor for now

16z HRRR looks to bring in a line of supercells through the i95 corridor between 6pm and 9pm... then rotates in a complex of heavy rain after midnight for N VA/DC/MD

Tornado Watch coming soon for western part of the CWA

Tornado Warnings starting from RLX in S WV

Looks like we should reach into the lower 80s for temps

Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1105 AM CDT Fri May 30 2025 Valid 301630Z - 311200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF CENTRAL AND EASTERN NORTH CAROLINA...MUCH OF SOUTH CAROLINA...AND EAST-CENTRAL GEORGIA... ...SUMMARY... Scattered to numerous severe storms are possible this afternoon and evening, with 55-70 mph gusts capable of wind damage extending from the Mid-Atlantic states into the Southeast. The potential for a few tornadoes exists from the Mid-Atlantic states into the Carolinas. ...Mid-Atlantic/Carolinas and Southeast... Water-vapor imagery shows a potent mid- to upper-level trough over the OH-TN Valleys with this feature forecast to move into the Mid-Atlantic states/Carolinas by late evening. In response to this shortwave trough, a deepening surface cyclone will move from the KY/WV border east-northeastward along a quasi-stationary front into southeast PA/NJ by evening. A trailing cold front will move across parts of the Southeast, Carolinas, and Virginia. Wind profiles across the warm sector of the deepening cyclone will be seasonably strong, but instability is expected to be tempered by weak midlevel lapse rates and substantial cloud cover. As large-scale ascent with the approaching shortwave trough develops across the warm sector, thunderstorms are expected to develop along and near the cold front. A mix of cells and linear bands will gradually evolve into broken band convective structures with time as storms move east. Strengthening 700-mb flow (40-50 kt) amidst diurnally steepened 0-2 km lapse rates will favor strong to severe gusts. Damaging winds (55-70 mph) are expected to be the primary severe hazard, although a tornado threat will exist primarily with bowing segments. Farther north, the northern extent of a destabilizing warm sector immediately ahead of the deepening surface low, will favor an increasing severe risk this afternoon. Scattered storm development is initially forecast near the higher terrain with additional cellular development expected (consistent signal in recent HRRR runs) in the northern VA to southeast PA corridor late this afternoon and especially into the evening. Given the moist low levels and favorably shaped hodographs in proximity to the surface low, have enlarged 5-percent tornado probabilities for a supercell-tornado risk. Some consideration for higher tornado probabilities was given, but confidence was too low at this time. Damaging gusts and large hail are also possible with the stronger storms.

10% tor probs were considered... woah @Kmlwx @high risk

Probably not, but LWX did mention the threat in its AFD oking at tonight, as the low slowly pulls away, some showers likely linger on the back side of the low as well. One thing of concern is the 850mb wind field on the back side of the low during the pre-dawn hours Saturday morning. Will have to watch for some sneaky strong wind gusts if there is a heavy enough shower to bring that wind down to the surface. The hi-res guidance has a concerning amount of agreement on some high-end wind gusts around 40 to 50 mph potentially reaching the surface, so it is something I am growing increasingly concerned about. This is something to keep an eye on, given that this would occur during a very sensitive time period, being during the overnight. Should this trend continue, a short-duration Wind Advisory may need to be considered. Perhaps if things are still convective in nature, they could be handled with short-fused convective warnings as well.

I don't see that on their Twitter page or main school page

Yup Farther north across VA/MD/DE, confidence regarding storm mode is lower, with some guidance suggesting the potential for discrete/semi-discrete supercells ahead of the front. These storms would have the potential for severe wind/hail, and potentially pose a tornado risk with stronger/more sustained storms. If confidence increases regarding the expected coverage of severe storms in this area, then higher severe probabilities may be warranted with the 1630z Convective Outlook.

@Ellinwood - on board and good for tornado potential

Was it supposed to be mostly sunny and mostly blue skies this morning?

Also, zones now say sunny and hot with highs around 90 for next Wednesday and Thursday

Flood Watch National Weather Service Baltimore MD/Washington DC 317 AM EDT Fri May 30 2025 .A wavy slow moving frontal system will meander about the area on Friday evening into the night. Anomalous moisture coupled with high rainfall rates should increase the risk of flash flooding over portions of this watch area. DCZ001-MDZ004>006-008-011-013-014-016>018-503>508-VAZ036>040-050-051- 053>057-501-502-505-506-526-527-301530- /O.CON.KLWX.FA.A.0008.250530T2300Z-250531T0800Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ District of Columbia-Frederick MD-Carroll-Northern Baltimore- Cecil-Southern Baltimore-Prince Georges-Anne Arundel-Charles-St. Marys-Calvert-Northwest Montgomery-Central and Southeast Montgomery-Northwest Howard-Central and Southeast Howard- Northwest Harford-Southeast Harford-Nelson-Albemarle-Greene- Madison-Rappahannock-Orange-Culpeper-Fairfax-Arlington/Falls Church/Alexandria-Stafford-Spotsylvania-King George-Northern Fauquier-Southern Fauquier-Western Loudoun-Eastern Loudoun- Northwest Prince William-Central and Southeast Prince William/Manassas/Manassas Park- 317 AM EDT Fri May 30 2025 ...FLOOD WATCH REMAINS IN EFFECT FROM THIS EVENING THROUGH LATE TONIGHT... * WHAT...Flash flooding caused by excessive rainfall continues to be possible. * WHERE...Portions of DC, including the following , District of Columbia, Maryland, including the following areas, Anne Arundel, Calvert, Carroll, Cecil, Central and Southeast Howard, Central and Southeast Montgomery, Charles, Frederick MD, Northern Baltimore, Northwest Harford, Northwest Howard, Northwest Montgomery, Prince Georges, Southeast Harford, Southern Baltimore and St. Marys, and Virginia, including the following areas, Albemarle, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park, Culpeper, Eastern Loudoun, Fairfax, Greene, King George, Madison, Nelson, Northern Fauquier, Northwest Prince William, Orange, Rappahannock, Southern Fauquier, Spotsylvania, Stafford and Western Loudoun. * WHEN...From this evening through late tonight. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - As a slow-moving frontal system tracks across the area, multiple rounds of showers and thunderstorms are possible. While initially posing a severe weather threat, a shift to a slow moving complex of moderate to heavy rain unfolds into the evening and night. Storm totals could reach 2 to 3 inches, locally nearing 4 inches in spots. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information.

It does now for most Flood Watch National Weather Service Baltimore MD/Washington DC 317 AM EDT Fri May 30 2025 .A wavy slow moving frontal system will meander about the area on Friday evening into the night. Anomalous moisture coupled with high rainfall rates should increase the risk of flash flooding over portions of this watch area. MDZ003-VAZ025>031-503-504-507-508-WVZ050>053-055-501>506-301530- /O.EXA.KLWX.FA.A.0008.250530T2300Z-250531T0800Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Washington-Augusta-Rockingham-Shenandoah-Frederick VA-Page-Warren- Clarke-Western Highland-Eastern Highland-Northern Virginia Blue Ridge-Central Virginia Blue Ridge-Hampshire-Morgan-Berkeley- Jefferson-Hardy-Western Grant-Eastern Grant-Western Mineral- Eastern Mineral-Western Pendleton-Eastern Pendleton- 317 AM EDT Fri May 30 2025 ...FLOOD WATCH IN EFFECT FROM THIS EVENING THROUGH LATE TONIGHT... * WHAT...Flash flooding caused by excessive rainfall continues to be possible. * WHERE...Portions of north central Maryland, including the following area, Washington, Virginia, including the following areas, Augusta, Central Virginia Blue Ridge, Clarke, Eastern Highland, Frederick VA, Northern Virginia Blue Ridge, Page, Rockingham, Shenandoah, Warren and Western Highland, and West Virginia, including the following areas, Berkeley, Eastern Grant, Eastern Mineral, Eastern Pendleton, Hampshire, Hardy, Jefferson, Morgan, Western Grant, Western Mineral and Western Pendleton. * WHEN...From this evening through late tonight. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - As a slow-moving frontal system tracks across the area, multiple rounds of showers and thunderstorms are possible. While initially posing a severe weather threat, a shift to a slow moving complex of moderate to heavy rain unfolds into the evening and night. Storm totals could reach 2 to 3 inches, locally nearing 4 inches in spots. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information.

00z NAM Nest looks interesting... granted the storms weaken by the time they get up here... but those look nasty in the SW parts of the LWX CWA

18z NAM NEST shows good amount of UDH swath just south of DC metro

Hmmm, from this morning LWX AFD The end of the week into this weekend is starting to look more interesting with each run of model guidance. Those two upper-lows may try to phase into one over the eastern CONUS during this timeframe. Should this occur, a powerful surface low could bring some impactful weather to the region. Lots of uncertainty at this point however, so going to keep it vague for now. Just know that this is a period to watch this week.

URGENT - WEATHER MESSAGE National Weather Service Baltimore MD/Washington DC 112 PM EDT Sat May 24 2025 MDZ509-VAZ503-WVZ501-505-250115- /O.NEW.KLWX.FR.Y.0005.250525T0500Z-250525T1300Z/ Western Garrett-Western Highland-Western Grant-Western Pendleton- 112 PM EDT Sat May 24 2025 ...FROST ADVISORY IN EFFECT FROM 1 AM TO 9 AM EDT SUNDAY... * WHAT...Temperatures as low as 34 will result in frost formation, especially in valleys. * WHERE...In Maryland, Western Garrett County. In Virginia, Western Highland County. In West Virginia, Western Grant and Western Pendleton Counties. * WHEN...From 1 AM to 9 AM EDT Sunday. * IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive outdoor plants may be killed if left uncovered. PRECAUTIONARY/PREPAREDNESS ACTIONS... Take steps now to protect tender plants from the cold

Did NWS Nashville lose power or shelter? All of their warnings and updates are coming from NWS Fort Worth the past 20 minutes

Sounds like another good soaking late Tuesday into Thursday... another 1-2"

New severe thunderstorm watch up for WV until 5am https://www.spc.noaa.gov/products/watch/ww0273.html URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 273 NWS Storm Prediction Center Norman OK 1130 PM EDT Fri May 16 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Far Southeast Ohio Western Virginia West Virginia * Effective this Friday night and Saturday morning from 1130 PM until 500 AM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Clusters of thunderstorms should spread eastward overnight while posing a threat for mainly scattered severe/damaging winds, with peak gusts up to 60-70 mph. Isolated hail and perhaps a tornado or two may also occur. The severe thunderstorm watch area is approximately along and 50 statute miles east and west of a line from 35 miles east northeast of Parkersburg WV to 5 miles west southwest of Bluefield WV. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes.