924 FXUS62 KRAH 301042 AFDRAHArea Forecast Discussion National Weather Service Raleigh NC 640 AM EDT Tue Sep 30 2025
.SYNOPSIS... High pressure to the north and the circulation around Tropical Storm Imelda will continue to bring a cool and moist northeast flow to the region through this evening. Canadian high pressure centered over Quebec and New England will extend into our region and bring a chilly airmass into our area on Thursday and Friday.
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.NEAR TERM /THROUGH TONIGHT/... As of 240 AM Tuesday...
* Light rain and drizzle will gradually taper off by the afternoon, with the extensive stratus layer slowly lifting
Weak upper level impulses embedded within the plume of tropical moisture from TS Imelda will continue to support widespread low clouds with periods of light rain and drizzle through mid to late morning.
By midday/early afternoon, as Hurricane Humberto gains latitude to the north and Tropical Storm Imelda turns east and begins to move away from the SE US coast, precip will taper off as mean layer flow becomes increasing NELY, resulting in isentropic downglide. This will be followed by low-level dry air advection through the evening and overnight. Skies will not completely clear out however, with some mid level ceilings overnight.
Highs will range from lower 70s northwest, to mid 70s east. NELY winds of 7 to 10 mph will increase to 10 to 15 mph after daybreak, with occasional gusts in the 20 to 25 mph.
Lows tonight will fall in the 60s, with some upper 50s possible across the northern Piedmont.
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.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... As of 240 AM Tuesday...
* Sunshine returns with seasonable temps
The lingering upper trough that has been parked over the region will finally shift south of the area late in the day. At the surface, high pressure over SE Canada will build south into the NE US and New England, leading to renewed sfc pressure rises across our area Wednesday evening into Wednesday night.
Subsidence in the wake of the exiting trough should help to scatter out a broken veil of mid and high clouds allowing for sunshine during the afternoon commute. Dry conditions will prevail, with another day of breezy NELY winds expected, with gusts of 20 to 25 mph into the afternoon.
Overnight, gustiness will subside Wednesday evening with mostly clear skies and weak CAA setting in. Expect some of the coolest temps since early September. Lows 50 to 55, with some upper 40s possible in cooler outlying areas of the northern Piedmont.
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.LONG TERM /THURSDAY THROUGH MONDAY/... As of 255 AM Tuesday...
* Fall-like conditions on Thursday and Friday with a mix of clouds and sun with highs in the upper 60s to mid 70s. * Temperatures moderate to above average over the weekend into Monday with mainly dry conditions.
The long term period will begin with modest mid and upper level ridging centered across the OH Valley with weak troughiness extending from the southwestern Atlantic into the northern Gulf. The ridge axis will slip east into VA and NC by late Friday as an upper trough organizes across the lower MS Valley and northern Gulf. At the same time, a 1032mb surface high will be centered across eastern Quebec on Thursday morning before the high shifts east and off the New England Coast by Friday night. As the high extends southwest into the mid-Atlantic and Carolinas, a fall-like airmass will be injected into the area. A cool northeast flow will result in morning low-level thickness values in the 1350s on Thursday and Friday mornings resulting in lows in the lower to mid 50s in most locations and perhaps some upper 40s in the cooler spots in the Triad and near the VA border. Highs will range in the upper 60s to lower 70s on Thursday and the lower to mid 70s on Friday. A fair amount of strato- cumulus clouds are expected on Thursday, especially from Raleigh north and east with noticeably fewer clouds on Friday. A northeast breeze is expected on Thursday with some gusts of 15 to 20 mph with a lighter northeast wind on Friday.
The upper ridge will move south and east over the weekend into Monday with an upper low forming and closing off across the northern Gulf coast. This setup will favor the development of a deep easterly flow across the southeast and potentially a coastal trough extending from FL northeast to the Cape Fear region. This will result in a gradual increase in moisture over the weekend into Monday with some guidance suggesting the potential for some showers along the Carolina and Florida coast that could push inland across SC and perhaps southeastern NC. Perhaps more notable will be the airmass moderation and moistening with highs on Saturday and Sunday in the upper 70s to around 80 with highs on Monday in the upper 70s to lower 80s. -Blaes
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.AVIATION /11Z TUESDAY THROUGH SATURDAY/... As of 64020 AM Tuesday...
Through 12Z Wednesday: Tropical moisture streaming north into the area from TS Imelda will continue to produce widespread IFR to MVFR CIGS with periods of rain and drizzle through mid to late morning.
Gradual improvement is expected during the afternoon as lift wanes and daytime heating lifts the stratus, with further improvement to VFR by late afternoon and early evening as drier air advects in from the north.
Additionally, NELY winds 7-10 kts will increase after daybreak, with occasional gusts in the 17-23 kts range expected, strongest at KFAY.
Outlook beyond 12z Wednesday: Surface high pressure extending south into the region will support predominately dry VFR conditions through Saturday.
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.RAH WATCHES/WARNINGS/ADVISORIES... None.
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SYNOPSIS...Blaes NEAR TERM...CBL SHORT TERM...CBL LONG TERM...Blaes AVIATION...CBL
NWS RAH Office Area Forecast Discussion