Guidance from GSP…..
PRECIP RATES THROUGH THE DAY ARE EXPECTED TO BE TAME, WITH FORCING
LIMITED TO RATHER SHALLOW ISENTROPIC LIFT. AS SUCH, ANY FREEZING
RAIN SHOULD BE WELL WITHIN THE BOUNDARIES OF WINTER WX ADVISORY
CRITERIA THROUGH THE DAYLIGHT HOURS. HOWEVER, PRECIP RATES WILL PICK
UP THIS EVENING INTO THE OVERNIGHT, AS THE BAND OF FRONTOGENETICAL
FORCING SHIFTS EAST. THIS IS WHEN THINGS COULD GET INTERESTING IN
TERMS OF ICE ACCRETION ACROSS THE BLUE RIDGE AREAS OF THE NORTHERN
MOUNTAINS. TEMPERATURES ARE EXPECTED TO GRADUALLY WARM THIS
AFTERNOON/ EVENING, AS THE PARENT HIGH WEAKENS AND MOVES OFF THE
COAST. HOWEVER, THE SURFACE PATTERN ACROSS THE NORTHERN CONUS AND
SOUTHERN CANADA IS ACTUALLY RATHER COMPLEX, WITH TWO ANTICYCLONES
EMBEDDED WITHIN A BROADER RIDGE. ONE OF THESE WILL BE STRENGTHENING
(TO > 1030 MB) AND LOCATED SOUTH OF HUDSONS BAY BY 00Z WED...I.E.,
MOVING INTO AN INCREASINGLY FAVORABLE POSITION FOR REINFORCING THE
CAD. THEREFORE, IT'S NOT AT ALL CLEAR THAT LOCATIONS ALONG THE
NORTHERN BLUE RIDGE...ESP EAST OF THE CONTINENTAL DIVIDE WILL WARM
ABOVE FREEZING BEFORE THE HEAVIER PRECIP RATES ARRIVE. AS A
CONSEQUENCE, IT'S ENTIRELY POSSIBLE THAT A NARROW AXIS OF DAMAGING
ICE (.25-.5") WILL DEVELOP ACROSS EASTERN AVERY COUNTY AS WELL AS
FAR SOUTHERN MITCHELL/YANCEY, AND AREAS ABOVE ~2500' IN
MCDOWELL/BURKE/CALDWELL. AFTER COLLABORATION WITH NWS BLACKSBURG,
THERE IS ENOUGH CONFIDENCE IN THIS SCENARIO TO UPGRADE TO AN ICE
STORM WARNING IN AVERY AND BURKE MOUNTAINS. FOR THE REST OF THIS
AREA, CONFIDENCE IS NOT AS HIGH THAT ENOUGH OF THE FORECAST ZONE
WILL SEE WARNING CRITERIA TO WARRANT AN UPGRADE, BUT WORDING TO THIS
EFFECT WILL BE MENTIONED IN THE UPDATED ADVISORY. OTHERWISE, NO
CHANGES ARE PLANNED TO CURRENT HEADLINES. OUTSIDE OF THE NORTHERN
MOUNTAINS, THE REMAINDER OF THE ADVISED AREA SHOULD SEE UNDER 0.1"
OF ICE, WITH ONLY MINOR TRAVEL DIFFICULTIES EXPECTED OWING TO
MARGINAL TEMPS AND WARM ROADS.
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