textproduct: Wakefield

WHAT HAS CHANGED

Updated aviation discussion for 06z/03 TAFs.

Heat Advisory was expanded to include to include all counties Thursday (excluding the MD and NC beaches).

KEY MESSAGES

1) Hot and humid conditions with heat indices around 105F expected through the rest of the week. Heat Advisories remain in effect for inland areas today and have been expanded to included the remainder of the forecast area (excluding the MD and NC beaches) for tomorrow.

2) There are daily chances for thunderstorms through Saturday. Some storms may be strong to severe with damaging winds gusts and large hail.

DISCUSSION

As of 305 PM EDT Wednesday...

KEY MESSAGE 1...Hot and humid conditions with heat indices around 105F expected through the rest of the week. Heat Advisories remain in effect for inland areas today and have been expanded to included the remainder of the forecast area (excluding the MD and NC beaches) for tomorrow.

High pressure remains stretched across most of the area this afternoon, leading to mostly clear to partly cloudy skies. The only area not encased in the sweltering heat is the coastal areas and the Eastern Shore. The coast is receiving some relief due to the onshore flow, while the Eastern Shore is seeing a combination of the onshore flow and a backdoor front that has buckled across that area. The MD Eastern Shore counties have had low cloud cover that has kept them in the lower 80s for most of the afternoon. The inland portion of the forecast area is currently observing temperatures in the 90s to near 100F at some sites, with heat indices in the lower to mid 100s. Unfortunately, this early September heat wave will continue through the end of the week as the aforementioned backdoor front will lift back to the north and winds will shift to the S-SW tomorrow. The ridge aloft will also remain intact across the Eastern U.S., and Thursday looks to be the hottest day of the week. Temperatures across our entire forecast area look reach the upper 90s to near 100F (lower to mid 90s across the Eastern Shore). With dew points in the lower to mid 70s forecast for tomorrow, most areas will see heat indices reaching Heat Advisory criteria of 105-108F, so have expanded the current Advisory to include all but the MD and NC beaches tomorrow. Looking ahead to Friday, the southern half of the area will likely need Heat Advisories, but how far north they will be needed will be dependent on the timing of a stronger frontal boundary that will be approaching the region on Friday. As this stronger front moves through the area late Friday through Saturday, we will finally see a much needed break in the heat. By Sunday, temperatures will be in the lower 80s, with refreshing 60s dew points.

KEY MESSAGE 2...There are daily chances for thunderstorms through Saturday. Some storms may be strong to severe with damaging winds gusts and large hail.

A line of thunderstorms is currently moving through the MD Eastern Shore counties this afternoon. This convection was spawned by an MCS near the eastern Great Lakes early this morning and has been riding along a boundary all the way to our area. With good shear to our north and abundant daytime heating, this line has remained strong as it moved SE-S, bringing strong winds. Hi-res guidance had a difficult time with this line earlier today, and a similar pattern is expected tomorrow, so we will likely be heading into tomorrow's possible severe weather with lower confidence in location and coverage. As of right now, some hi-res guidance is suggesting more widespread coverage, which is in-line with SPC's thinking since they have a majority of our area in a Slight Risk (level 2/5) for severe weather tomorrow. Granted, this severe threat is highly contingent on if convection does develop. There will be ample DCAPE and flow aloft will remain NW, so there are multiple factors in favor of stronger convection, but even with all these good parameters, confidence still remains on the lower side. The most favorable overlap of forcing, shear, and instability is expected Friday. At the surface, the aforementioned front to our north will finally make appreciable progress and descend into our local area. Aloft, NW flow will remain in place and progressively strengthen as the associated trough drops southward along the NE/Mid-Atlantic coast, increasing the deep-layer shear. This all suggests a bonafide severe wx threat for the majority of the area Friday, with the potential for several fast-moving clusters capable of widespread damaging winds, along with isolated supercells and large hail. The risk for storms (and any potential severe weather) Saturday is dependent on where the front is situated during peak heating. After the front moves through, the risk for severe weather becomes negligible as a much drier airmass filters in across the region through at least early next week.

AVIATION /06Z THURSDAY THROUGH MONDAY/

As of 130 AM EDT Thursday...

Developing fog and patchy low stratus are impacting the terminals early this morning. So far, RIC and SBY are the only ones to be impacted, but latest guidance suggests ORF and PHF will be added to the list before sunrise. Vsbys and CIGs will probably bounce around quite a bit between 06-11z with IFR or LIFR possible at times. Restrictions are expected to linger the longest at SBY, but should clear up around mid-morning. VFR should then prevail through the remainder of the 06z TAF period. Late evening thunderstorms are possible once again, but likely wouldn't reach terminals until after 00z.

Outlook: A stronger cold front is set to pass through the area Friday night into Saturday. The front will likely trigger scattered thunderstorms Thursday and Friday as it slowly sags southward. This may cause flight restrictions and strong wind gusts.

MARINE

As of 245 PM EDT Wednesday...

Key Messages:

- South to southwest winds increase on Thursday and Friday ahead of a cold front. Conditions are expected to remain below Small Craft Advisory criteria, but there could be wind gusts of 15kt at times.

- A cold front passes through the area Friday Night. This will allow winds to turn northerly then northeasterly as high pressure builds into the area from the north. Wind gusts may approach 20 kt late Fri night into Saturday. Weaker northeast winds on Sunday and Monday.

A weak backdoor front over the region has allowed winds to be northeasterly for much of the day over the VA and MD waters. Expect this front to move back north tonight allowing for southeast then south winds by Thursday morning. The tightening pressure gradient between the offshore high and the cold front to the west of the area will allow for winds to gust to 15 kt Thu afternoon/eve and again Friday.

The cold front is expected to pass through the area Friday night. This will allow winds to turn north Fri night then eventually northeast on Saturday as high pressure builds down from the north. Not a strong high pressure push behind the front. Still, simply due to the pressure rises and the north wind, expect winds to gust to 15 to as high as 20 kt late Friday Night into Saturday. Have ultimately increased NBM guidance a few knots Fri night into Saturday.

High pressure gradually builds over the area for Sunday and especially Monday leading to decreasing NE winds.

Seas generally 1 ft in the bay through Friday building to 2 ft Saturday. Seas over the ocean generally 2 to 3 ft.

CLIMATE

Record highs through Friday, 9/4:

Richmond: Record High:

Wed (9/2) 101/2014 Thu (9/3) 99/1984 Fri (9/4) 98/2023

Norfolk: Record High:

Wed (9/2) 99/2014 Thu (9/3) 97/1977 Fri (9/4) 96/1985

Salisbury: Record High:

Wed (9/2) 97/2014 Thu (9/3) 99/1930 Fri (9/4) 95/1944

Elizabeth City: Record High:

Wed (9/2) 96/1943 Thu (9/3) 97/2020 Fri (9/4) 98/1944

AKQ WATCHES/WARNINGS/ADVISORIES

MD...Heat Advisory from 11 AM this morning to 8 PM EDT this evening for MDZ021>024. NC...Heat Advisory until 8 PM EDT this evening for NCZ012>017- 030>032. VA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening for VAZ075>078-084>086-098>100-521>525-530-531. Heat Advisory until 8 PM EDT this evening for VAZ048-060>062- 064>069-079>083-087>090-092-097-509>520-528-529. MARINE...None.