Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
852 FXUS61 KLWX 270803 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 403 AM EDT Mon May 27 2024 .SYNOPSIS...
-- Changed Discussion --
A warm and humid air mass will persist through today. A cold front will push through the area tonight. A secondary cold front moves in by mid-week before high pressure builds in by Friday.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Some notable changes were observed in the latest guidance early this morning and it is mainly to delay convective initiation this afternoon and push back the timing of the frontal passage until mid evening. The severe risk also has shifted more east to areas along and east of I-95 and east of Rt 15 in northern MD. Latest CAMs this morning show several broken short line segments including bows developing across the northern neck of VA lifting NE into southern MD. Other short line segments are seeing on the reflectivity products over north central MD into southern PA. The primary threat remains damaging winds due to strengthening wind fields and moderate instability (~1500 J/kg), but a couple of tornadoes and isold large hail are also possible. Severe risk should diminish quickly after 00Z and be over completely by 02Z Tue.
-- End Changed Discussion --
&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
Scattered to numerous instability showers are expected Tue and Wed afternoons as additional shortwave energy rounding the base of the upper trough axis moves across the region. Shower activity on Tue may not produce any lightning at all, but has better chance of generating lightning on Wed due to higher CAPE values and steeper mid-level lapse rates/cooler temps aloft.
-- End Changed Discussion --
&& .LONG TERM /THURSDAY THROUGH SUNDAY/...
-- Changed Discussion --
Deep upper troughing will move overhead during the day Thursday. Skies should start out mostly sunny, but some fair weather clouds may form in response to daytime heating during the afternoon. A few sprinkles or a brief light shower can`t be ruled out either, but most locations should remain dry. High temperatures are forecast to reach into the upper 60s to mid 70s, with dewpoints only in the mid 40s. We`ll remain under the influence of upper troughing through the day Friday, but the trough axis will start to progress off to our east during the afternoon hours. This will result in another day of below normal temperatures within northwesterly flow. Sunny skies are expected, with high temperatures generally in the upper 60s to mid 70s. High pressure will build in from the Great Lakes Friday night. With clear skies, light to calm winds, and dewpoints only in the low to mid 40s, it will be a chilly first night of June, with low temperatures dropping back into the 40s to near 50 for most. Narrow upper ridging will build overhead next weekend, before the flow flattens out and turns more zonal in nature early next week. High pressure at the surface will move overhead Saturday morning, before progressing offshore later Saturday into Sunday. As this happens, a slight warming trend in temperatures will occur. Highs on Saturday are expected to reach into the mid-upper 70s, with upper 70s to lower 80s in the forecast for Sunday. Conditions are expected to remain predominantly dry this upcoming weekend, but a stray afternoon shower or thunderstorm can`t be ruled out on Sunday.
-- End Changed Discussion --
&& .AVIATION /08Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Showers and thunderstorms are likely to impact the main terminals this afternoon. The highest risk is at BWI and DCA with lesser chance at IAD and MRB. CHO appears to have the least risk of experiencing thunderstorms. Severe wind gusts are possible particularly at BWI and DCA. Threat should end by 00Z tonight. Prevailing VFR conditions and northwesterly winds are expected on both Thursday and Friday.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
SCA conditions expected today through tonight due to gradient winds. Special Marine Warnings are also likely to be required for thunderstorm winds greater than 33 kt. Sub-SCA northwesterly winds are expected on both Thursday and Friday. & .TIDES/COASTAL FLOODING... With increasing south/southeast flow, there will be a higher chance of minor flooding with this morning`s high tide. Straits Point, Annapolis, and DC SW Waterfront will be most susceptible. Westerly winds behind a cold front will lead to decreasing anomalies through the middle of the week.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...None. MD...Coastal Flood Advisory until 1 PM EDT this afternoon for MDZ014. VA...None. WV...None. MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ530- 535-536-538-542. Small Craft Advisory until 6 PM EDT this evening for ANZ531>534-537-539>541-543.
-- End Changed Discussion --
&& $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...KJP AVIATION...LFR/KJP MARINE...LFR/KJP TIDES/COASTAL FLOODING...LFR