Area Forecast Discussion

WHAT HAS CHANGED

May be issuing Coastal Flood Advisories within the hour based on latest trend in the tidal anomalies for Annapolis and Havre de Grace; otherwise, no other changes expected to the forecast.

KEY MESSAGES

- 1) Warming temperatures mid to late week as a cold front drops into the area and stalls.

- 2) Cooler air moves in this weekend, along with chances for showers.

DISCUSSION

KEY MESSAGE 1...Warming temperatures mid to late week as a cold front drops into the area and stalls.

A cold front will move across the region today. Rainfall will be little compared to the drought conditions that we have been experiencing over the past couple of weeks. Rain amounts could average 0.10 to maybe 0.25 inch and could be focused along and north of I-66 and US 50. A thunderstorm or two could also occur around mid-morning to midday given the lift from the front and some instability. A linger storm in a few spots in the afternoon too. Small hail, brief downpours and a wind gust over 45 mph seems the greater concerns with any thunderstorms.

Otherwise through the rest of the week, a warming trend in temperatures expected even after today's front drops through the area and stalls just to our south. High temperatures could push back into the lower to middle 80s by Friday ahead of another system likely to bring a return of rain by the second half of Friday.

KEY MESSAGE 2...Cooler air moves in this weekend, along with chances for showers.

A complex upper-level pattern will unfold across the region this weekend as upper ridging in place breaks down while two large upper lows (one over the Northern Rockies, one over the Northern Atlantic) start to interact. High pressure will strengthen off to our northeast, which will force a backdoor cold front to push further southwestward into our forecast area. Meanwhile, a decaying disturbance associated with the western upper low will track overhead. Showers appear likely this weekend as a result, with the greatest chances occurring on Saturday as the aforementioned upper disturbance moves through. There's still some uncertainty with respect to the ultimate positioning of the front, and as a result, there's still a wide range of potential temperatures. Locations on the warm side of the boundary may approach 70, while locations on the cool side will likely be stuck in the 40s and 50s. Chances for cooler conditions will be greater off to the north and east, while chances for warmer temperatures will increase toward the southwest. Chances for showers decrease further on Monday, with temperatures expected to fall near seasonable levels (highs in the upper 60s to low 70s).

AVIATION /07Z WEDNESDAY THROUGH SUNDAY/

VFR conditions continue through Friday. Some temporary sub-VFR conditions are possible with a weak cold front today. The front could bring brief -SHRA/-TSRA at the terminals this morning into this afternoon. Some places near CHO and areas to the east could end up dry but low confidence in pinpointing these areas as the front will be on its way across our region. Winds will be southwest becoming northwest with frontal passage this afternoon. Gusts will remain between 15 to 20 kts at the TAF sites. Some LLWS also possible as S/SW flow increases aloft ahead of the boundary.

Additional WAA showers are possible by Friday afternoon which could be accompanied by a few restrictions. Winds will be out of the NW on Thursday.

VFR conditions and light east to northeasterly winds are expected on Friday. Sub-VFR ceilings appear likely on Saturday, along with easterly winds and showers.

MARINE

SCAs continue through this morning with moderate southerly channeling expected behind a warm front and ahead of a cold front. Sub- SCA level winds are expected this afternoon through Friday with winds out of the SW to NW as a cold front crosses and stalls. This front may bring a few showers and thunderstorms mainly this afternoon.

Sub-SCA level NW to E/NE winds are expected over the waters Thursday/Friday. SCA-level gusts appear possible in easterly flow on Saturday.

FIRE WEATHER

RH will likely continue to rise across the Alleghenies today while holding steady elsewhere. RH may drop in around 40 percent south of I-64 this afternoon. Winds will likely gust 20 to 30 mph as they shift to out of the west along and west of I-81 and near and south of I-64 this afternoon. Given the downsloping flow, RH could drop more than forecast in the I-64 corridor (to near 30 percent) resulting in a locally elevated fire weather threat in those areas. Light rain amounts are expected (generally 0.10" or less) near and north of I-66/US-50 today, with additional rain potential Friday into the weekend.

TIDES/COASTAL FLOODING

Tidal anomalies continue to rise and thus we could be issuing Coastal Flood Advisories shortly at Annapolis and Havre de Grace. Will look into this closer in the next hour or so.

LWX WATCHES / WARNINGS / ADVISORIES

DC...None. MD...Small Craft Advisory until 8 AM EDT this morning for MDZ008. VA...None. WV...None. MARINE...Small Craft Advisory until 8 AM EDT this morning for ANZ530- 535-536-538. Small Craft Advisory until noon EDT today for ANZ531>534-537- 539>543.