Key MESSAGE 1, Today's fcst calls for lower Max temps by several degrees compared to yesterday's records, and thus AppTs will drop a few degrees as Tds remain relatively the same. Spots this afternoon have been bouncing right around the HeatAdvy criteria. Have continued to blend NBM with ECS/MAV/MET guidance which is closer to reality as NBM continues several degrees too high with MaxTs. Not a completely dry forecast for the entire FA this evening as outflow from convection originating W of the area colliding with the seabreeze may lead to some short lived pop up tstorms between 1700-2300EDT over the Wern born of the FA.
For tonight, increasing moisture with rising Tds behind a weak warm front lifting through the area will make for a very oppressive overnight with MinTs in the mid/upr 70s interior to low 80s coast.
Monday, temps continue to drop a few degrees again as thickness decrease with the decaying ridge. Mon MaxTs mainly in the low 90s inland to upper 80s coast. However, with the aforementioned higher Tds in place, heat indices may actually be a few degrees higher than today's readings. Contemplated extending the heat advisory through the Sunday night into the Monday afternoon period, though held off as convective initiation may occur by as early as noon Monday.
KEY MESSAGE 2, Return to a pattern of increased shower and tstorms chances Mon into Tue, possibly into Wed as well. A series of shortwaves, inland troughing, and a very slow moving backdoor front will converge to produce higher than climo coverage of showers and storms each afternoon to early evening, and PoP continue in the 50-70% range, with much needed rain across a good portion of ENC expected. Wind shear will be very low, suggesting storm organization will be very limited. However, as with any summer storm, cannot rule out some wet microbursts as PWATs will be quite high, in the 2.25" range and stronger mature storms will carry the potential for some gusty winds toward the end of their life-cycle. Because of this, SPC has outlined areas along and W of HWY17 in a Marginal Risk (1/5) of severe tstorms. Another round of decent covg of afternoon showers/storms possible Wed as the aforementioned boundaries may still be in place.
Beyond mid week, PoPs return back to climo (20-40%) as more typical seabreeze showers/storms return. Hts/thicknesses slowly build in the process as ridging begins to build once again, with heat indices 100-105 in the forecast.
KEY MESSAGE 3, Aforementioned ridging builds mid to late week into the weekend, as ensemble mean heights rise back to above normal, and forecast temps reach well into the 90s, pushing heat indices to potentially AoA 105 deg again as a very humid atmosphere will be in place as well. Efi for both Min/MaxTs are pushing into the 80th percentile esp late in the week.
KEY MESSAGE 4, With the aforementioned high heat and humidity expected, a very unstable atmosphere develops per med range guidance hinting at ML CAPES aoa 3.5k J/KG, and SFC based instability between 4-5k J/KG. As is typical this time of year, deep layer shear will not be too strong, but any storms that can develop with some upper level support could produce strong downdraft/microburst winds and very heavy rain characterized by PW's exceeding 2".
00z Monday through Friday
VFR conditions through the TAF period with the exception of a tempo group for potential IFR visibility issue overnight for OAJ due to a nearby fire. Otherwise expect clean conditions with prevailing southerly shifting to southwesterly winds at generally 5-10 kts gusting to the occasional 15kts. A few guidance sources show the potential for some MVFR stratus uncertainty for this is high at this time and have left it out of the TAFs for now.
Outlook (Mon through Thurs): Upper ridge breaks down Monday with shortwave energy bringing good chances for showers and thunderstorms and potential for sub-VFR conditions Mon into Tue, possibly into Wed as well. Beyond mid week, more typical iso to widely sct activity expected as ridging rebuilds into enc.
Light winds generally 10-15 kt will cont today, but some further increase in the afternoon to evening as thermal gradient tightens, but gusts generally remain at or below 25 kt. Seas cont around 2-3 ft with up to 4 ft possible across the outer zones.
Outlook (Mon through Wed): Bermuda high pulls offshore into Monday with a front slowly dropping south across the Mid- Atlantic serving to tighten gradient a bit and expect winds to increase to around 15-20 kt and seas building to 3-5 ft. Have issued SCAs for PamSound and coastal waters S of Oregon Inlet for winds 15-20G25-30kt as a result of the thermal gradient. The gradient relaxes Tue morning with winds returning to 5-15 kt. Weakening front moves into the waters on Wed, though as is typical in July, the front appears to wash out, with any Nern flow behind it short lived with return flow developing as early as Wed evening.
Nc, none. Marine, small craft advisory from midnight Monday night to 8 am EDT Tuesday for amz135. Small craft advisory from midnight Monday night to 10 am EDT Tuesday for amz152-154. Small craft advisory from 10 pm Monday to 8 am EDT Tuesday for amz156-158.
