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Morning discussion from LWX DISCUSSION... KEY MESSAGE 1...Severe weather is possible, mainly east of the Blue Ridge this afternoon into early evening. A slow-moving cold front arcs down the Saint Lawrence River Valley to the lower Great Lakes back into the central Great Plains. To the south, a largely stationary front was attempting to lift slowly northward as a warm front, and stretched from the Carolinas back to Oklahoma. Showers and thunderstorms were persistently trekking west to east along the northern front, with a weak surface low and MCV/shortwave crossing Illinois. This shortwave will be the impetus for convective development across the Mid-Atlantic later today as the local area sits in between the two aforementioned fronts. Most instability this morning is rather weak and elevated in nature, but is expected to increase rapidly in the I-95 corridor from south to north as higher moisture air advects into the area, as well as near the Appalachians ahead of an approaching shortwave, both by late this morning. For now, weak lift and CAPE is keeping things limited to a few WAA showers near the metros. Additional development, perhaps even deeper convective cores, is possible by as early as late morning given the anticipated rapid increase in CAPE and lift. Flow aloft is seasonably strong by late August standards, with a 100+ knot 300 hPa jet streak expected to pivot over the Saint Lawrence River Valley into northern New England by evening. The tail of this upper jet may actually strengthen and persist near the Mason-Dixon Line early this evening, which could briefly enhance large scale ascent locally via RRQ dynamics. In the mid levels, the previously mentioned shortwave has trended notably deeper and a bit slower over the last 12-24 hours. This brings the axis of the shortwave, its enhanced flow, and PVA across the Appalachians around midday, then across areas near and east of the Blue Ridge/Catoctin Mountains east to I-95 and the Chesapeake Bay during peak heating. In addition to bringing large scale ascent, this pushes effective deep layer bulk shear into the 35- to 50-knot range later today (highest north/northeast). Shear of this magnitude is favorable for sustained, organized updrafts, including line segments and supercells (discrete or line-embedded). Thermodynamically, the atmosphere will be very moist, especially further east. Strong low-level theta-e advection is expected to persist through early evening ahead of the approaching shortwave and cold front. Widespread clouds will limit heating somewhat, especially west of the Blue Ridge where the storm threat is notably less, but with the strong low-level moisture advection and slow-but-steady cooling aloft, the net result should be about 1000-2000 J/kg MLCAPE in the moist plume east of the Blue Ridge heading into this afternoon, possibly as early as late morning. The moist low-level advection beneath cooling aloft may also result in re-generative CAPE and multiple rounds of thunderstorms in any one location. This would be most likely from near the DC metro north and east where large scale ascent is strongest, with the added component of enhanced low-level convergence along bay or river breezes (and eventually composite outflow boundaries). Finally, PWs will approach or exceed 2 inches in the moist axis near and east of I-95 this afternoon into early evening. Deep warm cloud layers in the high PW airmass will yield heavy to extreme instantaneous and sub-hourly rainfall rates in the stronger precip cores. Individual cell motion is expected to be progressive (30-40 mph) given enhanced flow through the column and the potential for modest cold pool development with any persistent cells, clusters or line segments. However, the wavy slow-moving front approaching from the north may lie close to parallel to the mean steering flow at times, especially when modulated by outflow from potential multiple rounds of storms. This, coupled with the bay breeze which often takes on a similar orientation, plus the urban footprint that has seen heavy rain recently raises a (primarily urban/poor drainage) flash flood risk over the I-95 corridor in northeast Maryland, including the Baltimore area. The threat is a bit more conditional further south and west into areas like Annapolis and the DC/Capital Beltway region; these areas also feature urban sprawl and inherently lower FFG, but the training potential is more conditional based on favorable outflow or cell interactions given slightly further displacement from the synoptic front(s) and bay breeze. Multiple hazards are possible today, and are outlined below. Damaging Wind... Straight-line/downburst winds are likely the highest threat today, at least from an areal coverage standpoint. Tall, skinny CAPE profiles with modest pockets of mid-level dry air yield DCAPE of 600-800 J/kg, which would be marginally favorable for strong to severe downdrafts. Background mid-level flow may approach 40 knots around 700 hPa. With the high PW air and modest DCAPE, water-loaded downdrafts via precip drag would be possible especially with any bowing line segments or collapsing mesocyclones/mesovorticies. The lack of steeper lapse rates (hence modest DCAPE) should keep most wind gusts within the strongest storms in the 55-70 mph range, with more widespread 40-55 mph potential. Given heavy precip and late summer, leafed- up trees, would anticipate scattered to numerous instances of tree and branch falls and subsequent power outage potential. The risk is highest near and east of I-95 where storms are most likely to become linear and be a bit more intense, since they`re further east in the moist axis with a little more time to heat. To the west, especially west of the Blue Ridge, less moisture and heating should keep the coverage of more intense storms low. Tornadoes... A conditional risk for a brief spin-up is evident for most areas east of the Blue Ridge given the magnitude of low/mid-level flow and high PWs/lower LCLs. Relatively greater tornado potential may exist closer to the front near the I-70 corridor east of Frederick where surface winds will be backed and low-level SRH will be higher, especially in close proximity to the bay breeze along the western shore of the Chesapeake Bay into northeast MD. Potential would be further maximized by (1) discrete supercells occurring earlier when the synoptic low-level winds remain backed and SRH is higher on a broad scale, and (2) with any favorable QLCS surge/mesovortex interactions with residual outflow or the bay breeze. Although unlikely due to a lack of stronger 0-1 km shear/SRH and steeper lapse rates, robust 3CAPE near the bay could result in a conditional risk for a strong tornado if all of the above factors were to coalesce. Flash Flooding... We have been in a wetter pattern recently, but the majority of the region is still in or just coming out of drought. Poor drainage and urban areas are susceptible to heavy rain, especially the intense sub-hourly rates possible today, regardless. Additionally, areas near and just northeast of Baltimore have seen multiple episodes of heavy rain over the last few weeks. Individual storms should move pretty swiftly, but the slowing southwest end of any lines or clusters would orient parallel to the nearby surface front, bay breeze, and mean steering flow. This brings a risk of flash flooding to northeast MD in particular, with a more conditional risk further south and west into the greater DC metro. Hail... Although lapse rates aloft will be modest at best given the moist profiles, supercellular shear and modest mid-level cooling will be favorable for at least some marginal/spotty severe hail potential. Should mid-level shear/cooling be more potent or cells be more discrete, the hail risk could increase, but this seems unlikely given the otherwise tropical-esque airmass. The threat for severe weather and flooding appears highest between 2 PM this afternoon and 8 PM this evening, progressing west to east in one or two rounds. However, it may start a couple hours earlier further west (or on the bay breeze), and could linger through late evening over southern Maryland. By later this evening, the departure of large scale lift and the loss of daytime heating should end the severe/flood threat.

Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 650 AM EDT Thu Aug 20 2026 ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508- VAZ053>057-527-211100- Chesapeake Bay north of Pooles Island MD- Chesapeake Bay from Pooles Island to Sandy Point MD- Chesapeake Bay from Sandy Point to North Beach MD- Chesapeake Bay from North Beach to Drum Point MD- Chesapeake Bay from Drum Point MD to Smith Point VA- Tidal Potomac from Key Bridge to Indian Head MD- Tidal Potomac from Indian Head to Cobb Island MD- Tidal Potomac from Cobb Island MD to Smith Point VA- Patapsco River including Baltimore Harbor- Chester River to Queenstown MD-Eastern Bay- Choptank River to Cambridge MD and the Little Choptank River- Patuxent River to Broomes Island MD- Tangier Sound and the inland waters surrounding Bloodsworth Island-District of Columbia-Cecil-Southern Baltimore- Prince Georges-Anne Arundel-Charles-St. Marys-Calvert- Central and Southeast Montgomery-Central and Southeast Howard- Southeast Harford-Fairfax-Arlington/Falls Church/Alexandria- Stafford-Spotsylvania-King George- Central and Southeast Prince William/Manassas/Manassas Park- 650 AM EDT Thu Aug 20 2026 This Hazardous Weather Outlook is for the Maryland portion of the Chesapeake Bay, Tidal Potomac River, and I-95 corridor through central Maryland, northern Virginia, and District of Columbia. .DAY ONE...Today and Tonight Numerous thunderstorms are expected between about 3 PM and 9 PM. These storms may contain damaging wind gusts and potentially a couple of tornadoes, especially near northeast Maryland. There is also a threat of urban flash flooding, with the highest risk near and northeast of Baltimore.

Premier league starts tomorrow for those of you who enjoyed the World Cup.

you have been here long enough to know that reality does not exist here. This place runs on hopes, dreams, and trolls.

HREF has a widespread 1.5 to 2.5 potential. Localized 3-5 possible where the best training sets up. So a continuation of the heaviest summer rains coming after we get the 100° heat early in the season. Like our local version of a monsoon pattern.

Where is that from? Weathermodels.com? That looks very much like my extra tropical Pacific composite.

Starting to see +11 subsurface anomalies now.

No thanks.

I’ve been enjoying seeing and experiencing some monsoon convection since I arrived in CO. Saw some good ones on the way to and inside the awesome Rocky Mtn State Park. Trail Ridge Road is so spectacular that it’s almost beyond words. It went from 80s in Boulder to as cold as 53 at 11,500-12,000 feet up! It was cold enough there for a light jacket, especially when considering the steady winds up there.

word

It's been waxing and waning since February came into view. If you go to the actual Cfs2 site and check out the monthly forecasts, it's a little colder than what the TT site shows due to different time periods. https://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2seasonal.shtml

This isn't a new thought, scientists have been looking for weather impacts from accelerated warming in the arctic for a while. One hypothesis is a weaker, wavier jetstream, amplifying and slowing the progression of weather patterns. As far as I am aware this hasn't been proven with studies on both sides. Not aware of any findings on baroclinic storms either. Note that increased moisture compensates for weaker temperature gradients in baroclinic storms through increased heat release from condensation in clouds. One weather effect that has been found is a northward shift in the jet stream and storm track.

30 wind and 5 tor for Delmarva

The Arctic sea ice area has fallen back to near the 2013-24 mean: Perhaps this is partially related to the temps at 80+N finally rising to NN recently:

06z Day 1 OTLK moved SLGT back west a bit to just west of BR... MRGL back west of i81 corridor

We knew.

759 FXUS61 KCTP 200838 AFDCTP Area Forecast Discussion National Weather Service State College PA 438 AM EDT Thu Aug 20 2026 .WHAT HAS CHANGED... -- Changed Discussion -- * SPC upgraded southeast PA to a Slight Risk, highlighting potential for damaging winds and a tornado or two. * Increased rainfall totals today, including potential for a swath of 1-2"+ and an associated risk for isolated flooding. -- End Changed Discussion -- Hazardous Weather Outlook National Weather Service State College PA 449 AM EDT Thu Aug 20 2026 PAZ010>012-017>019-024>028-033>036-041-042-045-046-049>053-056>059- 063-064-210900- Elk-Cameron-Northern Clinton-Clearfield-Northern Centre- Southern Centre-Cambria-Blair-Huntingdon-Mifflin-Juniata-Somerset- Bedford-Fulton-Franklin-Northern Lycoming-Sullivan-Southern Clinton- Southern Lycoming-Union-Snyder-Montour-Northumberland-Columbia-Perry- Dauphin-Schuylkill-Lebanon-Cumberland-Adams- 449 AM EDT Thu Aug 20 2026 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Multiple rounds of moderate to heavy rainfall may lead to isolated instances of areal flooding today. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. $$ Hazardous Weather Outlook National Weather Service State College PA 449 AM EDT Thu Aug 20 2026 PAZ065-066-210900- York-Lancaster- 449 AM EDT Thu Aug 20 2026 This Hazardous Weather Outlook is for central Pennsylvania. .DAY ONE...Today and tonight. Strong to severe thunderstorms this afternoon will be capable of producing very heavy rainfall, damaging winds, and a tornado or two. .DAYS TWO THROUGH SEVEN...Friday through Wednesday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. $$

0z EURO could have been interesting for the east coast.. EPS also but sooo far out..

Great... Flood watch extended

Is it a trend? Other models showing decent amount of rain, especially southern areas.