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County Warning Area [CWA]: LWX
Regional NWS Weather Office: Baltimore, MD/Washington, DC/Sterling, VA
County Warning Area [CWA]: LWX
Regional NWS Weather Office: Baltimore, MD/Washington, DC/Sterling, VA
673 FXUS61 KLWX 091412 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1012 AM EDT Fri May 9 2025 .SYNOPSIS... A cold front will slowly move through the area today as low pressure moves northeastward from the Mid Atlantic coast. High pressure will prevail through the weekend. Low pressure will approach from the southwest toward the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... A dual area of upper lows are situated across southeastern Ontario and western Pennsylvania, respectively. The mean trough axis connecting these features extends southward from western New York down to the Central Appalachians. There is quite a moisture gradient as noted in the GOES-19 multi-channel water vapor imagery. Much drier air looms off to the west, while extensive cloud cover and showers persist across the Mid- Atlantic region. More specifically, multiple clusters of showers continue to pivot east-northeastward across the area, particularly east of the Alleghenies and north of I-66. Although moisture is relatively anomalous in nature, a lack of instability has generally held 3-hour rainfall totals to around 0.10 to 0.25 inches. For the rest of the morning into the early afternoon, waves of showers will persist given the wavy stalled frontal zone extending across St. Marys County through southern Delaware. Any threat for isolated thunderstorm activity would be along that mentioned moisture gradient seen on water vapor imagery. High- resolution models remain at odds with one another on whether such a threat will materialize. Will withhold mention of thunderstorms until confidence increases. Even if such storms do form, the instability should be shallow which suggests any storms likely will not get too strong. Skies start to clear from the southwest during the afternoon while showers become less widespread. Locations that get some sun could pop into the upper 60s to near 70s, while the rest of the area will remain in the lower to mid 60s. Any precipitation should end by this evening as the surface low moves farther up the coast and dry air advects into the area. For most of the area, cold advection will drop lows into the 40s. Some of the deeper western valleys could decouple, though there is some uncertainty with how low temperatures can get as winds aloft will likely remain elevated. Have issued a Frost Advisory for locations where valleys are most likely to approach freezing, with some potential for future expansion. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... High pressure will slide southwest of the area Saturday. Dry conditions will prevail, but it will be a bit breezy with a lingering gradient to the low over New England. Near normal temperatures are expected with highs in the lower to mid 70s and lows Saturday night in the mid 40s to mid 50s. A weak front will drop into the area Sunday but dissipate as it does so. High pressure will quickly build in from the eastern Great Lakes, with little effect on the tangible weather. Since heights will be rising, temperatures will be warmer despite the front, with highs in the mid to upper 70s and lows in the 50s. Dry weather will continue, but some cirrus may intrude from a cut off low over the southern states. && .LONG TERM /MONDAY THROUGH THURSDAY/... H5 pattern reveals large cut-off ULL across Louisiana to start the period. This feature will eject northward into the Mid-Atlantic through the early parts of the week as UL ridging over the southwest US kicks it east and ridging over the Atlantic steers it north. At the surface, high pressure will reside over the area Monday before shifting eastward into Tuesday. Late Tuesday into Wednesday an area of low pressure will move up the coast bringing a soaking rain. Ensemble probabilities for 1" of rain range from 30-60% across the area, so something to keep an eye on 5-6 days out. Thereafter, the long term looks to remain somewhat unsettled with multiple shortwaves moving through later next week bringing renewed chances for rain showers. In terms of temperatures, generally within a few degrees of climo norms. Tuesday and Wednesday look to be the coolest in terms of high temps due to rain and clouds. Moderating slightly by the end of the week. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... Light to moderate rain showers continue to pivot toward the east-northeast this morning. Consequently, ceilings remain along the fringes of IFR to MVFR. However, most recent trends have pulled ceilings to around 1,200 to 1,500 feet. As showers pass through, these could briefly lower at times. Some improvement is expected by midday/early afternoon as steadier rain exits. However, VFR may not completely return until late afternoon. A few northwest wind gusts to 20 kt could occur, but winds should generally be light. CHO may clear out this afternoon, offering an opportunity for heavier showers or thunderstorms to develop, but confidence in direct impact remains low at this time. VFR conditions will prevail tonight through the weekend. Northwest winds may gust 20-25 kt Saturday, especially in the morning. Lighter north winds are expected Sunday. VFR conditions Monday with light winds out of the southeast. Restrictions possible heading into Tuesday and Wednesday as low pressure and corresponding rain/clouds move through. Winds generally southeast Tuesday into Wednesday with gusts to 15 kts. && .MARINE... Winds may be somewhat variable through the day as a front pushes through and low pressure moves up the coast. One surge of winds may affect the waters from late morning through early afternoon, then there could be a bit of a lull. Winds will pick back up tonight, especially along the bay. Have issued a Small Craft Advisory for the wider waters today and tonight to account for these scenarios. Confidence is lower on the western tributaries, but some occasional gusts can`t be ruled out. A few thunderstorms may affect mainly the southern Maryland waters early this morning and again this afternoon. Confidence is higher for gusty winds on all waters Saturday, with a Small Craft Advisory in effect for that period. Winds will become lighter Saturday night. A weakening front will shift winds to the north Sunday, but advisories are not expected at this time. Winds could flirt with SCA criteria Tuesday into Wednesday depending on low track. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Small Craft Advisory until 6 PM EDT Saturday for MDZ008. VA...Frost Advisory from 2 AM to 8 AM EDT Saturday for VAZ503-504. WV...Frost Advisory from 2 AM to 8 AM EDT Saturday for WVZ501-505- 506. MARINE...Small Craft Advisory until 6 PM EDT Saturday for ANZ530-531- 539. Small Craft Advisory until 6 PM EDT Saturday for ANZ532>534- 537-540-541-543. Small Craft Advisory from 8 AM to 6 PM EDT Saturday for ANZ535- 536-538-542. && $$ SYNOPSIS...ADS NEAR TERM...ADS/BRO SHORT TERM...ADS LONG TERM...CPB AVIATION...ADS/BRO/CPB MARINE...ADS/CPB
Weather Forecast Discussion from: NOAA-NWS |
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