238 FXUS62 KRAH 071737 AFDRAH AREA FORECAST DISCUSSION National Weather Service Raleigh NC 1237 PM EST Fri Jan 7 2022 .SYNOPSIS... Arctic high pressure will build across and offshore the Mid-Atlantic states through Saturday night. Low pressure will move across the region Sunday and Sunday night, creating the next chance for rain. && .NEAR TERM /THROUGH TONIGHT/... As of 945 AM Friday... Water vapor satellite showed an upper-level low centered just north of Upstate New York, weak ridging along the Rockies, and zonal flow across NC. A tight pressure gradient from a 1032 mb surface high across the TN Valley and a 994 mb low off the MA coast will continue gusty NW winds across central NC today, with gusts of 20-25 mph expected throughout the afternoon. Cold air advection will continue today, with highs only reaching the mid-30s north to mid-40s south. However, these temperatures combined with breezy conditions, will make it feel more like the mid-20s north to upper 30s south. The surface ridge will build into the Mid-Atlantic through Saturday morning, helping to relax the pressure gradient and diminish winds across central NC tonight. Dewpoint temps will drop to the single digits and low teens as the ridge filters cold and dry air across the region. With winds diminishing and clear skies tonight, radiational cooling will allow temps to plummet into the teens north to the low 20s south. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... As of 400 AM Friday... Broad ridging aloft will persist across the Southeast this period, around a ~589 dm (500 mb) sub-tropical ridge forecast to develop across the Bahamas. Beneath that ridging aloft, modified Arctic high pressure will linger across the srn Mid Atlantic Sat, with sunny but cold conditions in the upr 30s to mid 40s. Clear and calm early Sat night will favor fast and strong radiational cooling through the first half of the night, followed by strengthening swly low level flow and moisture advection that will result in the newd expansion of an area of low overcast across the wrn Carolinas through Sun morning, including roughly along and west of US 1 in cntl NC. Temperatures will consequently steady to rise slightly late, after lows in the mid-upr 20s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 340 AM Friday... Sunday through Sunday night: As a deep upper low moves east through Canada on Sunday, the associated trough, amplified by the pair of shortwaves being absorbed into it, will slowly move eastward to over the Appalachians by Sunday night. The initial s/w that was moving through the Deep South will be the one to help pull in moist air off the Gulf. At the surface, as the high shifts farther out over the Atlantic, a warm front will lift through the area ahead of the advancing cold front. While the parent deepens over the Hudson Bay, a low moving through the ARKLATEX will shear and get absorbed into the larger scale trough. Central NC will be under the influence of warm advection, with return flow around the Bermuda high to the east and warm, moist flow off the Gulf ahead of the approaching cold front. The rain should move into the area late Sun morning/early Sun afternoon. The best chance and highest amounts of rain will occur Sunday aft/eve and into the early overnight period along and ahead of the cold front. The current fropa timing is still expected late Sun evening into early Sun night, with cold high pressure quickly beginning to build into the area in the wake of the front. For now, it still looks like the cold air will be chasing the precip out of the area, so still no threat for wintry precip. Expect a significant range in highs on Sunday, low 50s NW to mid 60s SE. Lows will depend on the fropa timing and arrival of cold air, but for now mid 30s NW to mid 40s SE expected, with the arrival of much cooler air delayed until Mon night. Monday through Thursday: The remainder of the forecast period should be dry, albeit cool. The upper trough will take its time moving east and out over the Atlantic Monday and Tuesday, with northwest flow dominating. A shortwave will move through the mid-Atlantic on Wed, but will be moisture starved. At the surface, cold high pressure will move through the Great Lakes and into the Northeast through Wednesday, extending southward through the mid-Atlantic. A dry cold front could push through the region mid-week in response to the shortwave aloft. Expect Monday to be breezy, with wind chill values about 5-10 degrees or so lower than the temperature. The pressure gradient will relax as the high moves into the area on Tuesday but high temperatures will be several degrees lower than Monday. Highs Tuesday will quite chilly, mid 30s NE to low 40s south. Lows in the upper teens to mid 20s expected both Monday and Tuesday nights, with wind chills Mon night in the 12-20 degree range. Gradual moderation is expected Wednesday and Thursday. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... As of 1230 PM Friday... Through 18Z Sat: NW wind gusts of 15-25 kt will continue through late afternoon, then diminish this evening. Otherwise, FEW/SCT high clouds will linger this afternoon, with clear skies tonight. VFR conditions are expected through the period. Outlook: IFR-MVFR stratus, and a risk of low-level wind shear especially over the Piedmont, will result late Sat night-Sun ahead of another strong Arctic cold front that will bring widespread rain to the region later Sun and Sun night. Otherwise, VFR conditions are expected early to mid-next week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...JJT NEAR TERM...JJT SHORT TERM...MWS LONG TERM...KC AVIATION...JJT