Area Forecast Discussion
Issued by NWS Charleston, WV

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS61 KRLX 201353
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
853 AM EST SAT DEC 20 2014

.SYNOPSIS...
A WEAK DISTURBANCE CLIPS THE AREA TODAY.  DRY SUNDAY.  SYSTEM MAY
CLIP MOUNTAINS MONDAY.  STRONG OCCLUSION CROSSES CHRISTMAS EVE.

&&

.NEAR TERM /THROUGH TONIGHT/...
845 AM UPDATE...
LOWERED TEMPERATURES TODAY ESPECIALLY THROUGH MIDDAY BASED ON
HRRR/LAV BENEATH THE CLOUD COVER.  MID LEVEL BAROCLINIC LEAF MOVES
NEWD THROUGH THE AREA THROUGH THIS EVENING...SO THE GIST OF THE POP
FCST LOOKED GOOD.

PREV DISCN...
MODELS SHOW AN UPPER LEVEL DISTURBANCE MOVING OVER THE REGION TODAY
WHILE A SURFACE LOW STAYS WELL SOUTH OF THE REGION. RADAR SHOWS LOTS
OF RETURNS TO THE WEST...BUT MOST OF THIS IS STRUGGLING TO GET
THROUGH A LOWER LEVEL DRY LAYER. SOME PRECIPITATION IN SOUTHERN IL
AND WESTERN KY IS MAKING IT TO THE GROUND WHERE THE MESO NAM SHOWS
THAT THE LOWER LEVELS HAVE MOSTLY SATURATED. BASED ON THIS...THINK
SOME LIGHT PRECIPITATION COULD MAKE IT TO THE GROUND AS THE
DISTURBANCE MOVES ACROSS OUR REGION...AS THE MESO NAM SHOWS THAT
MOISTURE MAKING IT INTO THE LOWER LEVELS HERE. THEREFORE WILL ADD
SOME SMALL POPS IN THE WESTERN COUNTIES TODAY AND THIS EVENING.

THE SYSTEM MOVES OFF TO THE EAST TONIGHT...BUT MESO NAM SHOWS THE
STRATUS DECK THAT RETREATS NORTHWESTWARD TODAY...PUSHING BACK
SOUTHEASTWARD TONIGHT. WILL GO ON THE WARMER SIDE OF MOS LOW
TEMPERATURE GUIDANCE IN SOUTHEAST OHIO DUE TO THIS DECK PERSISTING
THROUGH THE NIGHT.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
S/W RIDGING WORKS IN ON SUNDAY AS WAA SLOWLY BEGINS TO SPREAD
ACROSS THE AREA. THE LOW LEVEL FLOW TO VEER AROUND TO SE IN THE
AFTERNOON. THIS SHOULD HELP IN ERADICATING ANY LINGERING STRATUS
ALTHOUGH FLOW IS RATHER WEAK. WILL ALSO HAVE SOME WAA FROM THE S
TO HELP. UNFORTUNATELY...QUITE A BIT OF CIRRUS WILL BE STREAKING
IN FROM THE W IN THE AFTERNOON...TO FILTER WHAT SUNSHINE WE MANAGE
TO GET. INHERITED TEMPS CLOSE TO NEW GUIDANCE WITH LITTLE
TWEAKING.

CIRRUS SUNDAY NIGHT ALONG WITH STRATUS DEVELOPING ON E SLOPES
MAY KEEP TEMPS FROM BOTTOMING OUT. TREND IN MODELS IS FOR A WEAKER
SURFACE LOW ALONG SE COAST EARLY MONDAY. AS SUCH...PROBABLY
LOOKING JUST LIGHT PRECIP ACROSS THE MOUNTAINS MONDAY
MORNING...WITH THERMAL PROFILES SUPPORTING MAINLY -FZRA WITH A
BRIEF SHOT OF SN ON THE FRONT END. MOST OF THIS CONCERN WOULD LIKE
IN POCAHONTAS CO. ELSEWHERE...OUTSIDE OF THE MOUNTAINS...JUST HAVE
SOME SCHC POPS FOR A PASSING -SHRA IN THE MORNING. THERE MAY BE SOME
LINGERING -RA OR DZ IN THE NRN MOUNTAINS MONDAY
AFTERNOON...OTHERWISE LOOKING AT A DRY BUT CLOUDY END TO THE DAY.
TRIED TO CODE UP SOME WARMER TEMPS E OF I79 CORRIDOR TO W SLOPES
AIDED BY SOME DOWNSLOPING...WHERE SOME MID 50S POSSIBLE IN THE
AFTERNOON. HAVE GENERALLY UPPER 40S TO LOWER 50S ELSEWHERE. CAD
LOCATIONS WILL STRUGGLE TO GET OUT OF THE 30S HOWEVER.

ATTENTION QUICKLY TURNS TO WELL ADVERTISED STRONG SYNOPTIC SYSTEM
FOR MIDWEEK. UPPER TROF WILL UNDERGO SIGNIFICANT AMPLIFICATION
ACROSS THE PLAINS AND UPPER MIDWEST MONDAY NIGHT AND TUESDAY.
ENERGY ROTATING AROUND THE BASE OF THE TROF WILL CLOSE OF AN UPPER
LOW MIDWEEK AMID STRONG UPPER JET DYNAMICS. AS THIS OCCURS SURFACE
CYCLOGENESIS ACROSS THE DEEP SOUTH WILL OCCUR AND TRACK INTO GREAT
LAKES BY WEDNESDAY. WHILE THE MODELS VARY ON EVENTUAL LOWEST
PRESSURE WITH THIS...THEY ALL SEEM TO AGREE ON THE MAGNITUDE OF
PRESSURE FALLS WITH BOMBOGENESIS LIKELY TO OCCUR BEFORE BECOMING
VERTICALLY STACKED.

THIS ALL MEANS CHAOTIC SENSIBLE WX HEADING INTO CHRISTMAS. WITH
STRONG AND DEEP SE FLOW DEVELOPING TUESDAY AND TUESDAY
NIGHT...FELT A DRIER FORECAST WAS THE WAY TO GO EXCEPT ALONG THE E
SLOPES WHERE LIGHT RA OR DZ IS POSSIBLE. DID LEAVE SOME SCHC POPS
IN THOUGH BUT THINKING MAINLY DRY FOR DAYLIGHT HOURS TUESDAY. IT
WILL BE RATHER WARM DESPITE MID AND HI CLOUDS OVERHEAD. WARM GFS
LOOKS TO BE THE WAY TO HEDGE WITH LOW 60S A GOOD POSSIBILITY
ACROSS THE LOWLANDS AND ESPECIALLY DOWNSLOPE REGION JUST E I79
WHERE MID 60S IS NOT OUT OF THE QUESTION. QUITE A BIT COOLER ON
E SLOPES. SHRA CHANCES BEGIN TO INCREASE TUESDAY NIGHT...FIRST
ACROSS SE OH AND NE KY...INCREASING ACROSS REMAINDER OF CWA TOWARD
WEDNESDAY MORNING AS THE SURFACE LOW STRENGTHENS AND RESULTING
BAROCLINIC ZONE APPROACHES. LOWS TUESDAY NIGHT WERE HELD UP
SIGNIFICANTLY GIVEN THE AMOUNT OF DOWNSLOPING BL WINDS. TEMPS
WILL FALL QUICKLY BEHIND THE FRONT WITH SHSN EXPECTED. HIGHS
WEDNESDAY TRICKY AS CKB TO EKN MAY BE ABLE TO SNEAK UP TO NEAR 60
BEFORE THE FRONT CROSSES. AS THE COLD FRONT PUSHES THROUGH SUSPECT
SOME OF THOSE STRONG WINDS ALOFT WILL MIX DOWN...ESPECIALLY IN THE
POST FRONTAL REGIME. FLOW NEARLY PERPENDICULAR ACROSS ISENTROPIC
SURFACES ALONG WITH A TIGHT SURFACE GRADIENT AND CAA WILL ENSURE
STRONG GUSTY WINDS...CHRISTMAS EVE NIGHT AND EARLY CHRISTMAS DAY
ITSELF. 30 TO 35 KT GUSTS LOOKS TO BE IN THE CARDS...HIGHER ACROSS
THE MOUNTAIN RIDGES.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
ACTIVE WEATHER PATTERN CONTINUES IN THE LONG TERM PERIOD. STILL A
CHANCE FOR SOME LIGHT PRECIPITATION MONDAY NIGHT/ TUESDAY AS LOW
PRESSURE MOVES NORTHEAST ALONG THE COAST. EXPECTING PRECIPITATION TO
MOSTLY BE IN THE FORM OF RAIN...EXCEPT ACROSS THE MOUNTAINS THERE
-SN OR A -RASN WILL BE OBSERVED. AT THIS POINT...IMPACTS FOR THIS
EVENT LOOK MINIMAL.

FOCUS THEN SHIFTS TO AN UPPER LOW ACROSS THE MIDWEST...WITH SURFACE
LOW PRESSURE AND ASSOCIATED COLD FRONT TUESDAY NIGHT INTO WEDNESDAY.
OUT AHEAD OF THE FRONT...MOISTURE AND TEMPERATURES WILL BE ON THE
INCREASE...WITH PW VALUES PROGGED TO RISE OVER AN INCH...AND
TEMPERATURES EXPECTED TO BE WARM ENOUGH EVERYWHERE FOR PRECIPITATION
TO INITIALLY FALL AS RAIN. THIS WILL CHANGE HOWEVER ON
WEDNESDAY...AS A COLD FRONT MOVES THROUGH THE AREA TUESDAY
NIGHT/EARLY WEDNESDAY...WITH TEMPERATURES FALLING BEHIND THE FRONT
ON WEDNESDAY...GRADUALLY CHANGING ANY LINGERING PRECIPITATION TO
SNOW CWA WIDE. IN ADDITION TO THE SNOW...WINDS WILL PICK UP ALONG
AND POST FRONTAL PASSAGE. ALSO...A RUMBLE OF THUNDER CANT BE RULED
OUT DURING THIS PERIOD WITH THE FRONTAL PASSAGE.

THIS REMAINS A TRICKY SYSTEM TO FORECAST IN TERMS OF OVERALL
IMPACTS...AS GROUND TEMPERATURES MAY AT LEAST INITIALLY REMAIN WARM
ENOUGH...PARTICULARLY ACROSS LOWLANDS...TO LIMIT SNOWFALL
ACCUMULATIONS. HAVE HOWEVER DECIDED TO GO AHEAD AND HIGHLIGHT THE
STORM IN THE HWO...SINCE IT WILL AFFECT THE AREA CHRISTMAS EVE INTO
CHRISTMAS. SPEAKING OF CHRISTMAS DAY...AREA WILL BE UNDER THE
INFLUENCE OF THE UPPER LOW FOR AT LEAST THE FIRST PART OF THE
DAY...WITH PERIODS OF -SHSN.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
STRATUS DECK SHOULD GRADUALLY LIFT NORTHWESTWARD EARLY THIS
MORNING...BUT MAY REMAIN IN OHIO TODAY. A LOW PRESSURE SYSTEM
MOVING WELL SOUTH OF THE REGION WILL PROVIDE SOME CLOUDS TODAY AND
POSSIBLY SOME PRECIPITATION...MAINLY IN VA AND SOUTHEASTERN WV. SOME
MVFR CLOUD RESTRICTIONS ARE ALSO POSSIBLE IN VA AND SOUTHEASTERN WV.
AS THE SYSTEM MOVES AWAY...THE STRATUS DECK IS EXPECTED TO BUILD
BACK SOUTHEASTWARD OVER MUCH OF THE AREA TONIGHT.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...

FORECAST CONFIDENCE: LOW ON THE TIMING AND PLACEMENT OF THE STRATUS
DECK...MEDIUM OTHERWISE.

ALTERNATE SCENARIOS: TIMING OF THE STRATUS DECK MOVING NORTHWESTWARD
COULD CHANGE CONSIDERABLY. TIMING OF THE STRATUS DECK RETURNING
SATURDAY NIGHT COULD VARY.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
EST 1HRLY       09   10   11   12   13   14   15   16   17   18   19   20
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  M    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    M    M    M    M    M    M    M    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 12Z SUNDAY...
IFR POSSIBLE IN MOUNTAINS SUNDAY NIGHT MONDAY WITH A WINTRY MIX.
IFR POSSIBLE IN RAIN CHANGING TO SNOW TUESDAY NIGHT INTO WEDNESDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...RPY/SL/30/TRM
NEAR TERM...TRM/RPY
SHORT TERM...30
LONG TERM...SL
AVIATION...RPY





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.