039 FXUS61 KLWX 110735 AFDLWXArea Forecast Discussion National Weather Service Baltimore MD/Washington DC 335 AM EDT Thu Sep 11 2025
.SYNOPSIS... High pressure will remain to our north tonight as a wave of low pressure passes offshore. A dry front will dissipate as it approaches on Thursday, then another area of high pressure will drift toward New England this weekend, resulting in continued dry conditions.
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.NEAR TERM /THROUGH TONIGHT/... While low pressure is pulling away from the Mid Atlantic coast, north to northeast winds continue to advect moisture and clouds into the eastern half of the CWA. The shallow nature of this moisture combined with weak lift continues to result in patchy drizzle/light showers, as seen via radar and regional observations. Given the persistence of these showers all night, and model support, these showers will likely continue through mid-morning, though gradually shifting eastward as drier air filters in. This will also begin to push clouds towards the south and east by mid-late morning, with most areas seeing sun after noon. Highs today will reach the upper 70s to low 80s (upper 60s to low 70s in the mountains).
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.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... High pressure remains to the north on Friday with mostly sunny skies and temperatures returning closer to average for this time of year. Highs will be in the lower 80s (upper 60s to 70s in the mountains). Winds should remain light and out of the northeast.
Expect some patchy fog to develop in the sheltered valleys and areas that favor radiational cooling during the overnight hours. Low temperatures will generally be in the 50s. Lower 60s along the waters and in the metros.
Winds turn out of the south on Saturday, remaining light, as high pressure shifts a bit towards the east. A subtle mid-level height rise will result in slightly warmer temperatures Saturday afternoon, but overall the pattern remains very similar. Overnight lows jump a few degrees Saturday night in response to the southerly flow.
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.LONG TERM /SUNDAY THROUGH WEDNESDAY/... Overall the extended period remains quiet with dry conditions and near normal temperatures expected through the middle part of next week. Synoptically, will continue to watch the expansion of a 500 mb upper level ridge over the central U.S. Meanwhile, the upper trough over the area will push eastward as the ridge expands into the Ohio River Valley and Great Lakes region. At the surface, high pressure over northern New England will remain wedged down the eastern face of the Appalachians. This will lead to dry and tranquil conditions this weekend with high temperatures running near normal for most locations east of the mountains. A slight uptick in humidity may be noted with light easterly onshore flow banking Atlantic moisture east of the Blue Ridge. Skies will trend mostly sunny to partly cloudy Saturday with highs in upper 70s and low 80s (upper 60s and low 70s mountains). Mostly clear to partly cloudy skies are expected Saturday night with lows in the mid 50s to low 60s (deeper/sheltered river valleys could fall into the upper 40s). Some valley fog is possible late Saturday night into Sunday morning given the added moisture from onshore flow. Any fog would likely mix out as the inversion breaks Sunday mid morning.
An upper level low pressure system will track into the northeastern U.S Sunday and Monday with a broad 500 mb trough deepening overhead. The low pressure system will drag a cold front across the Mid- Atlantic and Northeast bringing rain chances back to the region. There still remain some uncertainty in regards to the coverage of rain and intensity given the residual dry airmass/high pressure system remaining nearby. For now, looking at chances of 15 to 20 percent mainly along and north of I-66/US-50 Sunday afternoon into Monday morning as main forcing tracks north of the region. Locations that do see rain will most likely see only a few one hundredths of an inch which doesn`t help with ongoing drought concerns. Elsewhere, mainly dry conditions are expected with increased cloud cover as the system passes through. Highs Sunday will reach into the upper 70s and low to mid 80s (mountains low 70s). Lows Sunday night will fall back into the 50s and 60s.
Broad Canadian high pressure over the Great Lakes wedges back into the area late Monday into Tuesday before settling nearby midweek. Tranquil weather is expected as a result along with near normal temperatures across the region. Expect high temps in the upper 70s and low 80s with overnight lows in the 50s.
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.AVIATION /07Z THURSDAY THROUGH MONDAY/... Mid-level clouds are still gradually pushing east, but very slowly at this time. Meanwhile, a shield of IFR to low-end MVFR CIGs has pushed almost all the way to the Blue Ridge this morning. This is at least temporarily dropping CIGs at most airports (aside form MRB) this morning. The deck is generally BKN, but at times will scatter out before filling back in. Expect periods of IFR to MVFR CIGs to continue through early morning as a result, perhaps even longer. Model guidance has been of little help in determining how fast these will scour out this morning. Patchy drizzle continues to affect the area too, and even some heavier showers up in northeast MD that is affecting BWI and MTN.
MRB and CHO may ultimately see some fog before sunrise this morning under mostly clear skies, although it is uncertain how far visibility drops. Fog could form at IAD if skies can clear before dawn, which is trying to happen at this time.
VFR conditions return for all areas later this morning and likely to continue throughout the weekend, outside of any mountain/valley late night/early morning fog. Winds out of the N to NE today and Friday will turn S to SW this weekend. Winds shift back out of the north and northwest early next week at less than 10 kts.
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.MARINE... No marine hazards are expected through Saturday night as high pressure returns to the region. Winds north to northeast 5 to 10 knots gusts to 15 knots today and Friday, before turning out of the south on Saturday.
SCA conditions are possible over middle and lower portions of the bay Sunday afternoon into Monday. Sub-SCA level winds are expected Tuesday and Wednesday as wedging high pressure sits nearby.
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.TIDES/COASTAL FLOODING... Due to low pressure moving off the coast, tides will remain elevated in the coming days. Anomalies are trickling down a little as the low moves farther offshore. However, slackening winds may allow some water to slosh northward today and Friday, with minor flooding possible in some locations during the afternoon and evening. The pattern doesn`t change appreciably, so spotty marginally minor flooding may continue into the weekend, especially since winds may eventually turn southerly.
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.LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None.
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SYNOPSIS...EST NEAR TERM...CJL SHORT TERM...ADS/CJL LONG TERM...EST AVIATION...ADS/CJL/EST MARINE...CJL/EST TIDES/COASTAL FLOODING...CJL/EST
NWS LWX Office Area Forecast Discussion