yoda

Nothing really initiating in N VA yet... a couple showers/storm N of DC metro... Baltimore metro already has numerous storms

Hmmm https://www.spc.noaa.gov/products/md/md1852.html Mesoscale Discussion 1852 NWS Storm Prediction Center Norman OK 1029 AM CDT Thu Jul 31 2025 Areas affected...southeastern Pennsylvania...New Jersey...Delaware...central Maryland...and adjacent portions of northern Virginia...including DC Concerning...Severe potential...Watch possible Valid 311529Z - 311800Z Probability of Watch Issuance...60 percent SUMMARY...Thunderstorms are in the process of developing, and likely to gradually intensify through 1-4 PM EDT, accompanied by increasing risk for potentially damaging wind gusts. A brief tornado might also be possible, particularly across parts of east central and southeastern Pennsylvania into central New Jersey. DISCUSSION...Perhaps aided by forcing for ascent downstream of a short wave perturbation progressing through the southern periphery of larger-scale positively tilted mid-level troughing overspreading the northern Atlantic Seaboard, thunderstorms appear to be initiating along a stalled to slow moving frontal zone, and east of a weak surface low, across the northern Mid Atlantic. This is occurring as insolation within a boundary-layer characterized by seasonably high moisture content (including mid 70s F surface dew points) erodes inhibition. Lapse rates are generally modest to weak, and the boundary layer is not forecast to become deeply mixed, due to the moisture, but profiles still appear supportive of CAPE on the order of 1000-2000 J/kg. Beneath the southern fringe of the stronger westerlies, where flow at altitudes as low as 500 mb is around 30-40 kt, deep-layer shear is strong and supportive of supercell structures, and perhaps an organizing cluster, with potential to produce strong surface gusts aided by heavy precipitation loading and evaporative cooling in downdrafts. Thermodynamic profiles appear generally warm with limited potential for severe hail. A brief tornado might not be out of the question, but low-level hodographs, particularly south of the surface front, are likely to remain generally weak. ..Kerr/Smith.. 07/31/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OKX...PHI...CTP...LWX... LAT...LON 39747713 40357698 40687612 40957453 40617390 39087505 38667600 38597718 39107734 39747713 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN

https://www.wpc.ncep.noaa.gov/metwatch/metwatch_mpd_multi.php?md=0832&yr=2025 Mesoscale Precipitation Discussion 0832 NWS Weather Prediction Center College Park MD 1101 AM EDT Thu Jul 31 2025 Areas affected...Mid-Atlantic... Concerning...Heavy rainfall...Flash flooding likely Valid 311500Z - 312100Z SUMMARY...Potential for slow moving, highly efficient thunderstorms with localized 2-3"/hr rates possible. Storm interactions may allow for localized totals of 2-4" totals and likely to induce flash flooding conditions by 21z. DISCUSSION...Surface analysis and visible GOES-E imagery shows a well defined stationary front within the Long Island sound intersecting to a surface low in the Delaware Valley before entering the terrain through the Lehigh Valley into south-central PA. A secondary surface wave near MDT/THV has a sharpening Lee Trough extending southward along the lee of the Blue Ridge toward Roanoke, VA and points south. Between the boundaries through the Mid-Atlantic, very moist and building instability can be seen with sfc Tds in the mid-70s with isolated low 80s dotted throughout the area. Weak southerly, confluent flow through 700-500mb is noted in CIRA LPW layers with enhanced moisture which totals over 2" (KIAD already at 2.16" at 12z) and will be increasing toward 2.25+" into the early afternoon. MLCAPE values have reached 2000 J/kg with weak capping noted and visible imagery shows expanding Cu field across much of the area, with some weak vertical development along major ridge lines of E PA, or near the stationary front/outflow boundary intersections across N NJ. Aloft, WV shows a very strong jet streak across the St.Lawrence River Valley with broad right entrance ascent pattern across much of the Upper OH valley through central NY into the Interior of New England. The convectively enhanced shortwave continues to shear/elongate from SSW to NNE with upstream core over E OH and into confluent flow will continue, along with the right entrance ascent provide ample DPVA and ascent profiles throughout the Mid-Atlantic. Bulk shear is greater near and north of the surface front likely to result in greater cell organization but is further distanced from deepest moisture/highest Theta-E near the Chesapeake Bay into SE PA. As such, there is likely to be difference in convective activity/manner across the area. Weak convergence along the lee trough/Blue Ridge is likely to expand areas of convection westward with time as well across NW VA. South of the Lehigh Valley, 12z guidance is increasing confidence in initial convective development through the 15-16z time frame. Initial thunderstorms will be very slow moving, but have stronger/broader updrafts with 14-15Kft of warm cloud layer for highly efficient rainfall production. While inflow will be weak, it is likely to pull multiple broad columns of that 2-2.25" Total PWat air to support 2-3"/hr rates by 18z given very slow cell motions (slower further south). Storm scale interaction/cold pool generation is likely to be the dominant mode of propagation, so interactions/collisions/mergers are possible and may result in increased duration to support localized 3-4" totals. The area remains saturated with 0-40cm soil ratios over 50-60% which is in the 70-80th percentile, combine that with proximity to large urban centers with impermeable surfaces; the shear rates are likely to overwhelm ground conditions quickly and result in flash flooding conditions; a localized considerable incident of flooding is possible as well. Gallina ATTN...WFO...BGM...CTP...LWX...OKX...PHI... ATTN...RFC...RHA...TAR...NWC...

85/78 at DCA at 10am... yucky

Initiation near Bel Air

Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 939 AM EDT Thu Jul 31 2025 .SYNOPSIS... A cold front will slowly move across the mid-Atlantic today through Friday. Strong high pressure will build into the area over the weekend, bringing below normal temperatures and humidity. High pressure weakens into next week while the next front is expected to slowly approaches from the south. Rain chances return by the middle of next week. && .NEAR TERM /THROUGH FRIDAY/... Excessively humid conditions are being observed across the region with dew points well into the 70s to near 80 and PW in excess of 2 inches (even 70+ Tds over the higher terrain). This will fuel thunderstorms with very heavy rain beginning in a few hours (roughly midday onward). A cold front will sag south into our region today. A strong shortwave trough will move over our area this afternoon and evening. A persistent southerly flow will provide deep tropical moisture to help fuel numerous heavy showers and strong to severe thunderstorms this afternoon and evening. Dewpoint temperatures in the low to mid 70s will result in revealing PWATs of 2.2 to 2.3 inches. One final day of hot and humid conditions today with the developing convection. Highs are forecast to be in the upper 80s to low 90s, with peak heat indices between 95-105.

SLGT risk up... 0/5/15 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jul 31 2025 Valid 311200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE MID ATLANTIC AND THE CENTRAL HIGH PLAINS... ...SUMMARY... A few strong storms, capable of mainly damaging winds, are possible across the Mid-Atlantic and Arkansas during the afternoon. Severe wind and hail producing storms are also expected across the northern Rockies into the central High Plains. ...Synopsis... An upper trough will traverse the Northeast while an upper ridge persists over the Central U.S. and broad upper troughing becomes established over the Interior West today. A surface low will develop across the Mid-Atlantic this afternoon with the passage of an embedded mid-level impulse within the broader trough, which will encourage widespread strong thunderstorm development. Across portions of Arkansas and immediate adjacent areas, a weak impulse will support the development of at least scattered strong thunderstorms amid ample buoyancy. Across the northern Rockies into the northern and central High Plains, an embedded mid-level impulse will result in the initiation of several thunderstorm clusters, which will move over the higher terrain during the afternoon. Given adequate buoyancy and shear in these regions, strong to severe storms are possible. ...Mid Atlantic... Thunderstorms should develop during the afternoon, as surface temperatures warm well into the 80s F, and quickly translate eastward given 40+ kts of 500 mb westerly flow. Surface dewpoints will reach well into the 70s F, supporting 2000-3000 J/kg MLCAPE despite mediocre mid-level lapse rates. The strong instability and 30-40 kts of effective bulk shear will encourage the development of strong multicells and perhaps a transient supercell. Damaging gusts are the main threat, though an instance or two of hail are possible, mainly during the afternoon and early evening hours.

Who are you?

81/76 at 3am at DCA... heat index near 90. The cool down cannot come fast enough.

Moderate risk on new Day 1

Thursday?

Looks like a semi-hit

Can see the lightning from the storms off to my west and northwest

I'm assuming @MN Transplant got hit decently too

https://x.com/AndyHazelton/status/1948861626939310217

Power has been out here for past 45 minutes... 1 of 73 people lol

Getting smoked here. Torrential rainfall and some pretty dangerous looking CG strikes

https://x.com/AndyHazelton/status/1947084436434301069

Its also throwing out a large southward moving outflow boundary on Radarscope

Numerous water rescues ongoing in College Park. Roads closed due to 5 feet of water on them reliminary Local Storm Report National Weather Service Baltimore MD/Washington DC 601 PM EDT Sat Jul 19 2025 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0601 PM Flash Flood College Park 39.00N 76.93W 07/19/2025 Prince Georges MD 911 Call Center Numerous roads closed due to high water in College Park. Water rescues ongoing. Water reported up to 5 feet deep on some roads. && Event Number LWX2506315

BULLETIN - EAS ACTIVATION REQUESTED Flash Flood Warning National Weather Service Baltimore MD/Washington DC 552 PM EDT Sat Jul 19 2025 The National Weather Service in Sterling Virginia has issued a * Flash Flood Warning for... East Central District of Columbia... Prince Georges County in central Maryland... * Until 900 PM EDT. * At 552 PM EDT, Around 3 to 5 inches of rain has fallen from thunderstorms upstream along Sligo Creek. Water rises around 10 feet occurred in 30 minutes. The water will drain through the Anacostia River this evening causing rapid rises through early this evening. Flash flooding is ongoing or expected to begin shortly. HAZARD...Life threatening flash flooding. Thunderstorms producing flash flooding. SOURCE...Radar. IMPACT...Life threatening flash flooding of creeks and streams, urban areas, highways, streets and underpasses. * Some locations that will experience flash flooding include... Bladensburg... RFK Stadium... Colmar Manor... Cottage City... PRECAUTIONARY/PREPAREDNESS ACTIONS... Turn around, don`t drown when encountering flooded roads. Most flood deaths occur in vehicles.

BULLETIN - EAS ACTIVATION REQUESTED Flash Flood Warning National Weather Service Baltimore MD/Washington DC 554 PM EDT Sat Jul 19 2025 ...FLASH FLOOD EMERGENCY FOR BETHESDA, TAKOMA PARK, CHEVY CHASE, SILVER SPRING, WHEATON... The National Weather Service in Sterling Virginia has issued a * Flash Flood Warning for... Southeastern Montgomery County in central Maryland... * Until 900 PM EDT. * At 554 PM EDT, Emergency management reports significant flash flooding along the Sligo Creek Watershed. Between 3 and 5 inches of rain have fallen. The expected rainfall rate is 1 to 2 inches in 30 minutes. Additional rainfall amounts of 1 to 2 inches are possible in the warned area. Flash flooding is already occurring. This is a FLASH FLOOD EMERGENCY for Bethesda, Takoma Park, Chevy Chase, Silver Spring, Wheaton. 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... Bethesda... Langley Park... White Oak... Takoma Park... Adelphi... Kemp Mill... Chevy Chase... North Kensington... South Kensington... Forest Glen... Hillandale... Martin`s Additions... North Chevy Chase... Wheaton-Glenmont... Friendship Village... Silver Spring... Wheaton... Calverton... Four Corners... Kensington... 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. Please report observed flooding to local emergency services or law enforcement and request they pass this information to the National Weather Service when you can do so safely. && LAT...LON 3899 7704 3897 7707 3896 7710 3897 7714 3904 7706 3904 7696 3899 7699 3898 7699 3897 7700 FLASH FLOOD...OBSERVED FLASH FLOOD DAMAGE THREAT...CATASTROPHIC EXPECTED RAINFALL RATE...1-2 INCHES IN 30 MINUTES

12z sounding PWATs at RNK was 1.60... WAL 2.12... IAD 1.99

https://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpferd

Uh oh .NEAR TERM /THROUGH TONIGHT/... Early morning RAP and observations analysis shows a stalled frontal boundary draped along the PA/MD border, stretching westward across the OH Valley. This region and the Mid-Atlantic are sandwiched between the Bermuda High (which is well west of its normal climo position in the western Atlantic) and a weaker surface high over the Upper Great Lakes. Abundant high level clouds this morning are expected to persist all day, with building low level clouds once mixing starts shortly after sunrise. This is going to keep highs lower today, mainly in the low to mid 80s. Peak heat indices reach the mid to upper 90s in Central VA. Southerly flow into the stalled boundary continues to advect deep tropical moisture into the region, so expect PWATs to jump well over 2" once again this afternoon. Aloft, a well timed shortwave trough looks to move across our area during peak heating and the main convective time window this afternoon to early evening. Modest deep- layer westerly shear around 30 knots will be enough to support organized deep convection, especially over the Shenandoah Valley and Central VA. More than enough instability is going to be present in this hot and humid airmass, with SBCAPE values of 1000-2000 J/kg. This is where SPC has a Slight Risk (level 2 of 5) for severe storms today, with damaging wind gusts as the main threat. The threat for thunderstorms really drops off quickly north/east of the Potomac River, with the Baltimore Metro to NE MD likely to stay clear for the most part today. The main threat is going to be flash flooding, which could be very significant in parts of the Shenandoah Valley. The tropical airmass will easily support rainfall rates of 1-2+" in 30 minutes, with hourly rainfall rates of 3-4" possible in the heaviest thunderstorms. Any area that sees either multiple rounds or training thunderstorms is likely to experience some flooding. Particularly worrying is the RRFS ensembles showing up to 40pct chance of seeing 100yr RI rainfall amounts (which equates to roughly 5" or more of rain) in the central Shenandoah Valley. The HREF max QPF also indicates the high-end potential of 4-7" of rain. Now these extreme amounts won`t be widespread and might not occur, but the potential is definitely there for worst-case scenario flash flooding. As a result, a Moderate Risk of flash flooding has been coordinated with WPC for the Central Shenandoah Valley, Blue Ridge Mountains, and portions of the Central VA Piedmont. Elsewhere, a Slight Risk of flash flooding extends north/east to around the Potomac River. A (Flash) Flood Watch has been issued. Scattered showers and thunderstorms could linger late into the evening. Some CAMs indicate outflow boundaries generating additional convection into the DC Metro and Southern MD late into the evening. Muggy conditions continue tonight as temps settle in the upper 60s to mid 70s. Low clouds and patchy fog are possible late tonight.