... Rainfall associated with Post Tropical Depression Sally will move east of the area today. In its wake, drier and cooler high pressure will dominate the weather through the middle of next week.
NEAR TERM /THROUGH TONIGHT/... As of 650 AM EDT Friday: The remnants of Sally continue to move to the Carolina coast this morning. A weak deformation zone and considerable low level moisture are moving out of the area taking the rain and drizzle with it. Low clouds should scatter out by mid morning, but mid and high clouds will remain. Gusty N to NE winds will taper off through the afternoon. Downsloping northerly flow and clearing low clouds will support highs a few degrees below normal.
Isolated showers may develop across the NW piedmont late in the afternoon into the early evening as a small area of forcing moves in from the NE. No significant rainfall is expected elsewhere. However, clouds do return, at least for portions of the night, as the low level flow turns more easterly and low level moisture lingers. Lows will be a couple of degrees below normal.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 325 AM EDT Friday: the short-term fcst picks up at 12z on Saturday with very broad upper trofing still centered over the NE CONUS and upper ridging to the west. Over the next 24 to 48 hrs, the upper trof will get pushed off the New England Coast as the upper ridge amplifies and spreads eastward. By the end of the period early Monday, the ridge axis will likely be centered just to our west with the trof axis just off the Atlantic Coast. At the sfc, cooler and drier air will be spreading over the area as broad and robust Canadian high pressure slides southward on Fri and Sat. A broad region of deeper moisture will remain just south and east of our fcst area as TD 22 remains over the NW Gulf of Mexico. Some cloudiness will linger on Saturday due to residual moisture from Post TC Sally and a slight Atlantic fetch. After that, skies will clear for Sunday and Monday as drier air spreads over the area. Temperatures will remain well-below normal thru the period.
LONG TERM /MONDAY THROUGH THURSDAY/... As of 220 AM EDT Friday: The extended fcst picks up at 12z on Monday with a robust upper trof moving off the Atlantic Coast as broad upper ridging spreads farther eastward and over our region. Over the next 12 to 24 hrs, TC Teddy will drift farther north and get absorbed by the above-mentioned upper trof. This will further amplify the trof and likely cause it to separate from the mean flow allowing a large, closed h5 low to develop by the middle of next week. As the period ends, the upper low/ trof will eventually lift northward as flat upper ridging spreads eastward. At the sfc, a broad 1030+mb high will be centered over New England as the period begins. Over the next 24 to 48 hrs, the high will shift southward as TC Teddy moves rapidly northward and then NW and remains just off the northern New England Coast. For the remainder of the period, the high is expected to remain centered over the Southeast and gradually weaken while what is currently TD 22 will remain in the far NW Gulf of Mexico. This synoptic pattern should keep cool and dry air over our fcst area thru the period with temps starting out well below normal for mid to late Sept. They will steadily climb thru the period, with values near normal by the end of the period late next week.