textproduct: Raleigh

WHAT HAS CHANGED

* Minimal changes with this forecast.

KEY MESSAGES

As of 200 PM Tuesday...

1) Marginal Risk (level 1 of 5) for isolated severe storms Wednesday afternoon/evening.

2) Low pressure off Florida will likely bring another round of rain to the region Friday night and Saturday.

DISCUSSION

As of 200 PM Tuesday...

KEY MESSAGE 1... Marginal Risk (level 1 of 5) for isolated severe storms Wednesday afternoon/evening.

As of early this afternoon, a surface low is in Quebec to the north of Lake Superior, with a cold front extending south across Lake Huron into Ohio and southwest into Texas. As the surface low moves northeast, the cold front will push to the east, remaining to the west of the Appalachian Mountains Wednesday morning. An upper level shortwave will be the primary forcing for showers very late tonight into Wednesday morning. Expect a wet morning commute in the Triad, with showers moving into the rest of the forecast area by late morning. While an isolated thunderstorm cannot be ruled out with this line of rain, instability along the line of showers will be very limited. The bulk of the showers should be east of I-95 by early afternoon. Another round of showers and thunderstorms will be possible as the actual cold front moves across the region late Wednesday afternoon and into Wednesday evening, but the severe thunderstorm threat will depend on how much clearing occurs between the two rounds of precipitation. The more clearing that occurs, the more surface instability that should develop which would fuel thunderstorms. There will be plenty of shear to work with for any storms that do develop, however the threat is conditional on whether any instability is able to develop. If any severe weather develops, it would likely be within 2-3 hours of sunset. The primary severe weather threat will be damaging winds, with a secondary threat of tornadoes. Overall rainfall is expected to be between a quarter and a half inch.

KEY MESSAGE 2... Low pressure off Florida will likely bring another round of rain to the region Friday night and Saturday.

Wednesday's cold front will move east, moving offshore and extending southwest back into Georgia and the Gulf Coast by Thursday morning. Originally having a northeast/southwest orientation, the northern half of the front will push southeast, with the front eventually aligned east to west along the Gulf Coast on Friday. As a stronger wave of low pressure develops along the front, the low will move northeast along the Atlantic Coast Friday night into Saturday, bringing rain back into the forecast. The forecast has not changed too much with the most recent model cycle, and confidence is still highest in both occurrence and amounts of precipitation to the southeast, with the northwestward extent still to be determined. Rain should come to an end early Sunday morning, and could range anywhere between a quarter inch and an inch.

AVIATION /17Z TUESDAY THROUGH SUNDAY/

As of 1230 PM Tuesday...

An area of mostly MVFR ceilings now over the NC wrn Piedmont, to IFR ones through ~18Z, may develop as far east as RDU while otherwise lifting and scattering to low VFR this afternoon. Generally sswly surface winds will gust to near 20 kts at times through sunset, strongest and most frequently over the Piedmont.

IFR-MVFR ceilings and another area of mostly stratiform rain are expected to overspread cntl NC generally between 10-16Z Wed, first at INT/GSO.

Outlook: Scattered showers and storms are expected to develop along and possibly just ahead of a cold front forecast to progress across cntl NC during the late afternoon and evening Wed. Another chance of flight restrictions and rain will accompany an area of low pressure forecast to track across or just south of the Carolinas late Fri night-Sat.

RAH WATCHES/WARNINGS/ADVISORIES

None.