... High pressure will continue to progress eastward across the Mid- Atlantic Region this afternoon into tonight. This high pressure system will move off the East Coast Sunday afternoon into Sunday night. A low pressure system in the Southern Plains and its associated warm front will increase rain chances late Sunday into Monday. The trailing cold front will track across The Carolinas and northeastern Georgia late Monday night into early Tuesday. High pressure returns Tuesday before another low pressure system impacts the region mid-week. High pressure moves back in for Friday.
NEAR TERM /THROUGH SUNDAY NIGHT/... As of 1000 pm: Strong upper jet streak hovering just to the north of the cwa will likely spark some mid- to upper-level clouds across parts of the area tonight. Shortwave ridge axis will continue to propagate towards the region during the near-term with a potent sfc high gradually sinking southward into the Carolinas during the day Sunday from the central Appalachians. The sfc high will slowly push downstream of the cwa and eventually offshore Sunday afternoon. This will introduce return flow for the southern Appalachians by late Sunday, ahead of a low-level cyclone that goes through slight cyclogenesis over the Southern Plains. With the return flow, winds will veer from the E/NE to the S/SW by Sunday evening and light QPF response is shown per model guidance over the southwestern facing slopes by 00Z Monday as the boundary layer begins to moisten. WAA will likely kick-off activity as the onset of precip will have to fight off a very dry airmass. The airmass will be dry enough to keep RH levels between 25-35% during the first half of the day. With light winds expected, don't bank on any fire weather products being issued, but precautions should be taken for any fire related shenanigans Sunday due to the persistent dry conditions. Precipitation should begin to fill into the cwa overnight Sunday into early Monday morning once the WAA associated with a developing warm frontal boundary pushes over the region under the warm sector of the low pressure system to the west. Temperatures will be below normal for min temps tonight with radiational cooling in store, while near-normal values are likely Sunday for max temps.
SHORT TERM /MONDAY THROUGH TUESDAY/... As of 1205 pm EST Saturday: We are still expecting a weak impulse to ripple thru the broad WSW flow aloft, and in conjuction with developing/northeastward lifting llvl baroclinic zone, a period of rain remains probable at some point Sunday night into Monday. The progged orientation of the better forcing and deeper moisture will result in the greatest rainfall cvrg and magnitude acrs Western NC during this first half of the period. Despite considerable cloudiness, with the influx of milder air within the developing warm sector could boost Monday's maximum temperatures as much as 10 deg F above climo in the southern tier of the cwfa. As the cwfa emerges into the warm sector, afternoon insolation could aid in developing weak instability in far southern sections. Cannot rule out some weak in situ cold air damming persisting near or just north of I-40 through late day Monday, and maxes will remain a touch under guidance for this reason here.
The most notable aspect of Tuesday's forecast will be the brief period of very mild conditions ahead of the approaching trailing cold front. It is shaping up to be one of those mild cool season days where the morning minimum temperature is about where the normal high should be and as the clouds breakup, piedmont temperatures could approach 70. Will plan on running just small residual shower chances through Tuesday morning as associated moisture and forcing is looking increasingly paltry with the cold frontal passage.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 200 pm EST Saturday: It is looking like unsettled wx conds will develop again on Wednesday as quickly eastward ejecting plains low pressure aids in reactivating stalled baroclinic zone to our south, blossoming pcpn shield north into the piedmont. NBM precip chances have crept upward into the likely range for the southern tier by Wed afternoon. There still remains medium range model differences with respect to the development and deepening of robust cyclone as energy pivots through the Carolinas Wed nite. But at this stage of the game, a period of decent forcing and deeper moisture still is timed for Wednesday night and the inherited sensible wx of likely pcpn chances regionwide is on track. Temperatures still seem warm enough for liquid pcpn east of the mountains with some lingering chances of an northern tier rain/snow mix. In the mountains snow showers should commence Wednesday night and then continue in the northwest upslope flow moisture and cold advection behind the wave through Thursday. Elsewhere, dry slotting should wrap in from the southwest fairly quickly during the day on Thursday. Dry llvl ridging returns from the west on Friday with the onset of southerly, but still dry, llvl return flow next Saturday.