A cold front will sweep east across the area late tonight, with a reinforcing front following Monday night. High pressure then returns for the middle to latter half of next week.
Until 6 pm this evening As of 0145 Sunday, Warm front has lifted N of the area with strongest convection pushing N of the FA. Scattered showers remain possible through rest of the overnight but activity is expected to wane in the early morning hours just before sunrise.
An upper level shortwave will translate east across the Upper Midwest through tonight. Well ahead of this feature, strengthening southerly flow will allow a warm front to lift north through the Carolinas. Increasing warm/moist advection along the advancing boundary should be supportive of scattered showers and thunderstorms developing from south to north after sunset. Despite nocturnal stabilization of the boundary layer, increasing moisture aloft should allow a plume of modest elevated instability to develop in the presence of 40-50kt effective deep layer shear. The lack of stronger instability, plus only modest forcing, should limit the risk of strong to severe thunderstorms tonight. However, if any stronger/more sustained core can be maintained, there could be a low- end risk of small hail.
ENC is expected to be warm-sectored for much of the day today, with warm low-mid level temps aloft leading to a moderate to strong capping inversion. This plus a lack of appreciable forcing is expected to limit the risk of daytime convection. The one exception is along the developing seabreeze in the afternoon, as some short term guidance suggest this may support a late-day risk of isolated thunderstorms. While this scenario appears unlikely, the combination of MLCAPE of 500-1000j/kg and 50kt+ deep layer shear could support a marginal severe thunderstorm risk just inland of the seabreeze (primarily a wind risk). Of note, machine learning guidance has backed off some on the severe potential, but continues to show a low- end signal. We'll continue to monitor this potential should greater instability and/or stronger forcing be realized. For now, carrying a dry forecast during daylight hours, but have raised PoPs in the seabreeze area to just below mentionable (PoP<15).
Otherwise, it is expected to be breezy and unusually warm for early November, with highs warming into the mid to upper 70s just ahead of the seabreeze. Obx capped MaxTs in the upper 60s to low 70s thanks to the cooling shelf waters.
6 pm this evening through 6 am Monday As of 0220 Sunday, Front enters the FA from the W around midnight with nearly meridional flow from midlevel up as upper low digs S across Great Lakes and Indiana, pushing upward leg of trough aloft across the Wern half of NC through the overnight. Convective precip is expected ahead of the boundary as it races across the FA. Some instability will remain from this afternoon's heating and the ample speed and directional sheer will keep a chance of more organized cells to carry some threat of damaging wind gusts with a lower, but non-zero threat, of hail. Temp gradient will be tight behind the front with burst of initial CAA leading to temps cooling into the mid 40s over the Coastal Plain in the early morning hours, low to mid 50s coast. Precip wanes from W to E in the early morning hours, but not directly behind the front as moisture still streaming in from the S above the frontal inversion will lead to some stratiform rain expected behind the front. This light rain could linger into Monday Morning along the portions of the Inner and Outer Banks.
Monday through Saturday As of 0245 Sunday,
Key Messages
- The coldest air of the season arrives Monday night into Tuesday. --- Freeze Watch has been issued for all of Mainland ENC --- Nonzero chance for wintry mix for Nern-most zones
A strong northern stream trough will move to the East Coast Monday, bringing the coldest airmass of the season thus far. Behind Sunday night's cold front, strong CAA and gusty NW winds will develop on Monday, with MaxTs in the mid 50s and MaxT perhaps failing to reach the 50 degree mark on Tuesday. For Tuesday, especially, this would be more than 15 degrees below normal for this time of year. Lows on Monday night are expected to drop below freezing with upper 20s to lower 30s across most inland areas and SWern zones away from the water, and mid 30s to around 40 along the coast. I would like to see clearer skies through more of the overnight, especially right around/after sunset when we typically get the cratering of SFC temps, but some midlevel cloud coverage streaming from SW to NE over the FA could spoil this potential. However, the clouds are not expected through the entire overnight period and I still think the airmass carries a great chance of subFreezing Mins. This cloud coverage represents an area of low- mid level moisture beneath the upper low which, in conjunction with a stout embedded midlevel shortwave traversing the region, may support a brief period of light rain showers transitioning to light snow showers along the HWY 264 corridor late Monday night into early Tuesday morning. Several ensemble members from both the Canadian and the ECMWF show this potential, select regional models, as well as the blended guidance from the NBM. The forecast will continue to reflect this potential, but at this time, no impacts are expected with accumulations expected to be minimal.
The high pressure axis will slide offshore late Tuesday with SW return flow developing, which may keep temps from dropping quite as cool Tuesday night, but with light winds and clear skies, areas that decouple could drop below freezing once again.
High pressure remains centered across SECONUS Wednesday with southerly flow bringing warming temperatures, but still 5-10 degrees below normal with highs in the lower 60s. A mid level shortwave pushes across the Mid-Atlantic Wednesday night with an attendant sfc trough/front pushing through the area, however the airmass remains very dry and don't expect much in the way of clouds, let alone precip, with this system. Deep westerly downslope flow ahead of ridging sliding across Sern CONUS will actually bring a few degrees of warming temps on Thursday with highs expected in the mid 60s. High pressure builds into the area Friday before sliding offshore first half of the weekend with highs in the low to mid 60s.
12z Sunday through Thursday As of 7 AM Sun, The area will be in the warm sector today ahead of an approaching strong cold front. Low clouds will clear out slowly this morning, and some brief MVFR conditions may return. Vfr conditions will continue through the day and into this evening with increasing SW winds. By tonight, scattered showers and thunderstorms will develop along the front as it moves across NC, with additional low level moisture pooling ahead of the front as well. This will likely lead to at least MVFR ceilings developing around midnight and lingering for most of the overnight hours before drier air clears out clouds from SW to NE early tomorrow morning. With convection possible, there will also be a risk for temporary IFR conditions developing.
Outlook: Behind a strong cold front early next week, mostly VFR conditions are anticipated with much cooler and drier air moving in.
As of 0245 Sunday,
Key Messages
- Thunderstorms possible tonight through Sunday night
- Gale Watches issued for all coastal waters and PamSound Monday evening into Tuesday afternoon
- Elevated to moderate marine impacts likely to last through mid- week with another period of brief Gales possible over outer coastal waters WED afternoon
Southerly winds build through the day accompanied by a risk of thunderstorms. Southerly winds will peak Sunday this afternoon and evening ahead of a cold front approaching from the west. During this time, southerly winds of 10- 20kt are expected, with occasional gusts to 25kt possible over the warmest coastal waters. Seas of 2-3ft build to 3-5ft by this evening.
A strong cold front moves through early MON morning with winds flipping around to the NW behind it by sunrise Monday. The strongest post- frontal winds arrive late Monday into Monday night as a reinforcing cold front moves through with renewed mixing and a strong pressure gradient. Probabilistic and deterministic guidance continue to show a strong signal for 20-30kt winds, with frequent gusts of 30-35kt. Gale watch has been issued late Monday into Tuesday afternoon. Another brief period of Gales possible second half of Wed. Either way, SCA conditions will be in play through the middle of the week. Seas of 6-10ft are expected Monday night into Tuesday. This may be followed by a renewed surge of southerly winds on Wednesday, with seas peaking as high as 5-9ft south of Cape Hatteras.
Winds and seas finally begin to lay down by Thursday as high pressure builds over SECONUS eventually sliding off the coast first half of the weekend.
Nc, freeze watch from Monday evening through Tuesday morning for ncz029-044>047-079>081-090>092-094-193>196-198-199. Marine, gale watch from late Monday night through Tuesday afternoon for amz135-150. Gale watch from late Monday night through Tuesday afternoon for amz152-154. Gale watch from Monday evening through Tuesday afternoon for amz156-158.
