043 FXUS62 KRAH 280836 AFDRAH AREA FORECAST DISCUSSION National Weather Service Raleigh NC 335 AM EST Fri Jan 28 2022 .SYNOPSIS... Canadian high pressure will weaken over the Mid Atlantic and Carolinas today, while low pressure organizes off the Southeast coast. That coastal low pressure will undergo rapid intensification off the coast of NC and VA tonight, as a vigorous mid and upper level trough pivots east across the Carolinas. Arctic high pressure will follow and build across the Southeast through Saturday night. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM Friday... ...Winter Weather Advisory for 1-2 inches of Snow Has Been Issued Tonight through Early Saturday for All of Central NC... Overview: A potent mid-level shortwave trough over the southern Great Plains this morning will dive eastward and will continue to deepen/amplify as the two branches of the jet stream phase over the SE US late today and tonight. In response to the incredibly strong synoptic scale ascent/h5 height falls, an area of low pressure off the SE coast will gradually deepen through this evening as it lifts north off the Carolina Coast, followed by rapid deepening and bombogenesis on Saturday as it moves north up the Atlantic Seaboard. Meanwhile, over interior sections , a reinforcing Arctic cold front will move NW to SE across central NC during the evening and early overnight hours. Today: With the coastal low well offshore, mostly dry conditions will persist through the daylight hours. Under a persistent mid- level cloud deck, highs today will range from lower 40s north to mid/upper 40s south. Tonight: The arrival of the strong synoptic scale forcing/lift associated with the amplifying northern stream trough diving into the region, coincident with the surface cold front pushing southeast through the area, will lead to the development of precip across the western NC that will translate east overnight. The resultant deep column cooling will result in a fairly efficient/quick change-over from rain to snow, with any transition p-type of freezing rain/sleet being very short-lived and inconsequential. Models are in relatively good in agreement and have stabilized wrt the all-so critical liquid equivalents overnight, ranging from near one-quarter of an inch across the NW Piedmont to just under one- tenth of an inch across the coastal plain. Similar to the previous forecast, expect the highest snowfall totals of 1 to 2 inches across the NW Piedmont/Triad, where the highest water-equivalent is forecast and where the best potential for banding exists. While some locally higher amounts of 3 inches are possible across the NW Piedmont, the precip banding signal in the models is not as impressive as it was 24-36 hours ago. Otherwise, snow amounts are expected to taper off west to east across the forecast area, with the potential for the well noted mid-level dry punch/slot to significantly cut into the snow totals across the I-95 corridor. Additionally, winds will pick up overnight, gusting 25 to 35 mph as the strong CAA commences and the pressure gradient tightens. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... As of 330 AM Friday... Any lingering snow across the coastal plain counties will exit the forecast area by mid morning. In the wake of the deepening low pressure system moving up the mid/northern Atlantic coast, expect cold and blustery conditions with wind gusts of 25 to 35 mph gradually waning during the afternoon. Highs in the upper 20s/lower 30 north to mid 30s south. However, the blustery winds will result in wind chills/apparent temps in the upper teens north to lower/mid 20s south. Clouds will scatter out with sunshine returning from west to east during the late morning and into the afternoon. Winds will eventually decouple overnight making for very cold temps Saturday night, especially in areas where there is adequate snow cover. Lows ranging from lower teens north to upper teens south with wind chills in the single digits north to lower teens south. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 245 AM Friday... Cold Sunday with moderating temperatures through Monday through mid- week. A wet period returns with warm air Thursday. A clipper system within our mid/upper trough over the east coast on Sunday will cross the Great Lakes will dive southeast into the Mid- Atlantic states Sunday afternoon and evening, before moving offshore overnight into Monday. The only impact from this will be mid and high-clouds streaming into the Carolinas as the low to mid-levels are very dry with surface dewpoints in the single digits. The ridge axis will move east of the central NC Sunday afternoon allowing a moderating SW return flow. Expect partly sunny skies with highs in the upper 40s SW ranging back into the upper 30s NE. Additional cloudiness associated with the clipper low and the return flow albeit light should keep temperatures up somewhat - expect lows mostly in the mid to upper 20s. Monday through Wednesday: Northwest flow at mid and upper levels will eventually transition to a more zonal west-southwesterly flow by midweek. This should favor a gradual warming trend with highs in the upper 40s to lower 50s Monday rising 5-10 degrees above normal to the mid-upper 50s/lower 60s by Wednesday as the low level flow becomes S-SW. An 80-90 kt jet streak oriented northwest to southeast from the Great Lakes into western NC on Mon may promote orographic cirrus during the day, but otherwise quiet weather is forecast Monday through Wednesday. A much warmer and wetter period expected Thursday. The latest model guidance continues in relatively good agreement for our next weather system to approach the area during this period Thursday and Friday. The GFS/ECMWF show a deep mid-level shortwave trough on Wednesday over the southwest US that tracks east into the Midwest and Ohio Valley Wednesday night into Friday. The associated sharp cold front (with arctic air again behind this front) is expected to reach the area Thursday evening and night. Warm air ahead of the front will result in showers with no ptype issues. The highest POP (likely) should affect the entire region beginning in the NW Thursday spreading east across central NC late Thu. Highs Thursday are expected to be in the 60s, with lows in the upper 40s, some 10-15 degrees above normal. Turning colder again late Friday behind the arctic front. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... As of 110 AM Friday... Periods of mid and high-level (VFR) ceilings will continue across cntl NC today, downstream of a vigorous upper level trough that will amplify across the MS and TN Valleys. Lift and a related band of precipitation accompanying that trough will pivot east across cntl NC tonight. The precipitation will likely begin as a brief period of MVFR rain at INT/GSO, then transition to moderate to heavy snow with LIFR conditions for a few hours after 00Z Sat. The precipitation band, initially rain then changing to snow --and sub-VFR conditions-- will then likely arrive at RDU and FAY around 06Z and RWI between 08- 12Z Sat. Lastly nwly surface winds will become strong and gusty into the 25-35 kt range with the passage of an Arctic cold front and following very cold/dry air and return to VFR conditions that will sweep east across the region overnight. Outlook: Once conditions improve to VFR from west to east late tonight into Saturday morning, VFR conditions are then expected to persist through Tue. && .RAH WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from midnight tonight to 11 AM EST Saturday for NCZ027-028-042-043-078-089. Winter Weather Advisory from 6 PM this evening to 6 AM EST Saturday for NCZ007-021>024-038>040-073>075-083-084. Winter Weather Advisory from 9 PM this evening to 9 AM EST Saturday for NCZ008>011-025-026-041-076-077-085-086-088. && $$ SYNOPSIS...MWS NEAR TERM...CBL SHORT TERM...CBL LONG TERM...Badgett/Kren AVIATION...MWS