Area Forecast Discussion
Issued by NWS Blacksburg, VA

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156 FXUS61 KRNK 171125 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 725 AM EDT Sun Sep 17 2017 .SYNOPSIS... High pressure will remain over the region into early next week resulting in mainly dry and mild weather over the next few days. Jose should track north, off the east coast Monday and Tuesday, before sliding just east of New England on Wednesday. && .NEAR TERM /THROUGH TONIGHT/...
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As of 230 AM EDT Sunday... Overall forecast remains similar to that of Saturday with the region under surface high pressure while having a weakness aloft to the north between upper ridging both offshore and to the southwest. This while within a weak low level convergence pattern per more northeast flow east of the mountains and weak west/northwest flow out west. Short term guidance again attempts to produce enough lift within this regime to result in isolated shallow convection this afternoon beneath dry air aloft. Again appears the best shot at showers will be just north of the region, closer to the core of the weak wave aloft, and perhaps northeast sections given better northeast flow under this feature aloft. Latest ensemble Cams and the HRRR show this along the northern Blue Ridge early this afternoon with very spotty nature coverage elsewhere mountains at best. Thus will keep in a mention and adjust coverage a bit but still no more than 20 pops for now. Otherwise will again see areas of mid clouds along with patchy fog early before heating of low level moisture helps trend toward developing cumulus during this afternoon. Should again be another very warm afternoon per slight warming aloft and strong heating within rather light overall easterly flow. Appears can add on a degree or two to highs from Saturday with low/mid 80s east and 75-80 west. May again see residual late day clouds spread out into a leftover trapped strato-cu layer this evening before clearing out overnight as any isolated showers quickly fade with loss of heating. With dewpoints still quite moist to the northwest of Jose, expect another round of at least patchy fog espcly west where winds should be lighter. Lows again similar to the past few overnights with most in the 58-65 range except slightly cooler valleys.
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&& .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... As of 220 AM EDT Sunday... The overall synoptic pattern will continue to feature an eastern ridge/western trof through midweek with a subtle influence from hurricane Jose as it moves northward just off the coast. Circulation around Jose will push some low level moisture into the region on northeasterly winds Monday, with enhanced convergence and orographic affects from the Blue Ridge westward yielding a chance of showers. As Jose pulls off to the northeast on Tuesday, winds will become northwesterly and allow some weak shortwave energy upstream to bring just a slight chance for an isolated shower west of the Ridge. Better energy will stream in our direction Wednesday with a chance for showers and thunderstorms west of the Ridge during the afternoon. With no fronts moving through to change the airmass, expect little change in temperatures for the next several days. Expect highs generally in the low to mid 80s east of the Blue Ridge with mid to upper 70s west. Lows will be in the low to mid 60s east to middle and upper 50s west with cooler readings in the valleys. && .LONG TERM /THURSDAY THROUGH SATURDAY/... As of 250 PM EDT Saturday... An upper level trough will move over the east coast states Thursday and Thursday night. Underneath this trough is a weak surface high that is expected to wedge south into the Carolinas Thursday night and stay through next weekend. Warm air gliding over this wedge and increasing isentropic lift may keep the skies overcast with light rain or drizzle falling through the day Friday. An upper level ridge moves over the wedge by Saturday which will help remove moisture and lift over the area. This upper level ridge will likely play a role in the track of the next tropical system approaching the southeast US. Temperatures will remain warmer than normal through the workweek. Temperatures fall back towards normal over the weekend. Normals for late September range from the mid 70s to lower 80s. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/...
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As of 715 AM EDT Sunday... Redevelopment of the mid deck canopy beneath the leftover weakness aloft has led to widespread VFR cigs across the north and east with mainly clear skies far west early this morning. This has also put a lid on fog development with most vsby reductions outside of the terminal locations over the west where things have stayed clear longer. Models continue to show uncertainty in regards to cloud coverage through the morning with some quickly clearing clouds/fog out, while others take until midday to erode the mid deck VFR cigs. For now will go a bit slower in going over to a SCT-BKN cumulus field with areas of sub-VFR likely for a couple hours in fog as well, mainly KBCB/KLWB as fog starts to move around with heating early on. Still expecting any fog/stratus to erode by 14-15z/10-11am with a transition to VFR SCT/BKN cumulus. An isolated shower or two could occur but mainly north and too iffy to include mention at this point. Expect may see another round of high end strato-cu or mid deck canopy redevelop overnight as moisture again gets trapped beneath the inversion aloft. This may again produce a round of VFR cigs with added sub-VFR conditions with fog/stratus in the valleys. Winds are light and variable/calm for much of the TAF period. Increasing easterly gradient flow may allow for a light northeasterly component to the wind by this afternoon across eastern locations, with speeds less than 10 kts. Extended Aviation Discussion... Overall persistence forecast to prevail for much of next week with strengthening high pressure remaining in place between Jose offshore and weak cold fronts approaching from the west. This should maintain good flying weather outside of early morning fog/stratus through late next week, with only isolated diurnal showers possible each afternoon.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...MBS LONG TERM...MBS/RCS AVIATION...AL/AMS/JH

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