FXUS61 KRLX 101512
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1012 AM EST THU DEC 10 2009
.SYNOPSIS...
GUSTY WINDS CONTINUE TODAY BEHIND DEPARTING LOW. HIGH PRESSURE WITH
COLD BUT DRIER CONDITIONS TODAY THROUGH SATURDAY. ANOTHER STORM
SYSTEM MOVES IN FOR LATER IN THE WEEKEND. COLD FRONT TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...UPDATED
SOME CHGS MADE WITH THE MORNING UPDATE. A BAND OF MAINLY -SN IS
WORKING ITS WAY ACROSS THE LOWLANDS ATTM. WENT DETERMINISTIC WITH
POPS WITH THIS BAND AS IT MOVES THROUGH THE LOWLANDS OVER THE NEXT
FEW HRS...WITH NORTHERN MTNS SEEING -SN THROUGH THE AFTN.
OTHERWISE...SCT FLURRIES THROUGH MIDDAY. WITH THERMAL TROF ALONG
OH RVR 00Z...COULD SEE A TRANSITION TO MORE OF CONVECTIVE/CELLULAR
NATURE...WITH SHSN MORE IN THE OFFERING DURING THE MAX HEATING HRS
AMID A FEW BREAKS IN THE CLDS. ONLY EXPECTING A DUSTING WITH THE
-SN BAND...MAYBE AN INCH OR TWO ACROSS THE NORTHERN MTNS WHERE
DURATION WILL PLAY A FACTOR. SHOULD SHSN MATERIALIZE DURING THE
EARLY AFTN...A LOCALIZED INCH COULD RESULT ACROSS THE NORTH.
GUIDANCE CONT TO SHOW TEMPS REBOUNDING TO NEAR FRZING ACROSS THE
LOWLANDS THIS AFTN...WITH SOME BREAKS IN THE CLDS SHOWING UP.
WITH TEMPS CURRENTLY RUNNING IN THE MID 20S...DECIDED TO KNOCK
DOWN AFTN HIGHS A TICK OR TWO...AS CAA WILL CONT THROUGH THE AFTN.
NO OTHER CHGS MADE TO FCST ATTM.
PREVIOUS FCST DISCUSSION BELOW...
MUCH DRIER WEATHER IS EXPECTED ACROSS THE FORECAST AREA IN THE
NEAR TERM AS THE LOW PRESSURE SYSTEM...CURRENTLY CENTERED OVER THE
GREAT LAKES...FINALLY PULLS OFF TO THE NORTHEAST...ALLOWING HIGH
PRESSURE FROM THE WEST TO BUILD IN. STILL EXPECTING GUSTY WINDS TO
CONTINUE FOR MUCH OF THE NEAR TERM AS SURFACE PRESSURE GRADIENT
BETWEEN THE EXITING LOW AND BUILDING HIGH REMAINS. THESE WINDS ARE
EXPECTED TO LESSEN THURSDAY NIGHT ACROSS MOST OF THE CWA AS THE
CENTER OF THE HIGH IS FINALLY ABLE TO MOVE CLOSER TOWARDS THE
REGION. HOWEVER...GUSTY WINDS WILL CONTINUE ACROSS THE HIGHER
TERRAIN OVERNIGHT AS WINDS OF AT LEAST 30-40+ KTS REMAIN AT 850MB.
ALTHOUGH MUCH OF THE FORECAST AREA WILL REMAIN DRY THURSDAY...A
FEW LIGHT SNOW SHOWERS ARE EXPECTED TO CONTINUE THROUGH EARLY
THURSDAY AFTERNOON OVER NORTHERN WV...AND NORTHERN MOUNTAIN ZONES
AS STRONG WESTERLY WINDS ALOFT...IN CONJUNCTION WITH A SHORTWAVE
MOVING THROUGH OHIO/NORTHERN WV...AFFECT THE REGION.
HIGH TEMPERATURES THURSDAY WILL BE MUCH COLDER THAN IN RECENT DAYS.
MODELS INDICATING 850MB TEMPERATURES RANGING FROM -13 TO -17C ACROSS
THE FORECAST AREA...CREATING MAX TEMPS IN THE MID 20S TO LOWER 30S
ACROSS MUCH OF SE OHIO AND THE WV LOWLANDS...WITH TEMPS IN THE MID
TEENS TO LOWER 20S OVER THE HIGHER TERRAIN. THIS IN COMBINATION WITH
GUSTY WINDS...WILL CREATE WIND CHILLS IN THE SINGLE DIGITS TO MID
TEENS ACROSS THE WEST VIRGINIA LOWLANDS AND SE OHIO TODAY...WITH
WIND CHILLS IN THE SINGLE DIGITS OVERNIGHT. OVER THE HIGHER
TERRAIN...WIND CHILLS WILL RANGE IN THE SINGLE DIGITS TO BELOW
ZERO...ESPECIALLY TONIGHT. THINKING COVERAGE OF WIND CHILL
TEMPERATURES BELOW -10 WILL BE ENOUGH TO WARRANT A WIND CHILL
ADVISORY TONIGHT OVER RANDOLPH AND POCAHONTAS COUNTIES.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
HIGH PRESSURE SAILS ACROSS THE AREA FRI AND SAT...BRINGING A WELCOME
BREAK IN THE WEATHER. PRESSURE GRADIENT BETWEEN LOW PRESSURE EXODUS
VIA CANADIAN MARITIMES AND HIGH PRESSURE BUILDING INTO THE AREA FROM
THE SW WEAKENS FRI WEAKENS OVER THE AREA...WITH GUSTS STILL CLOSE TO
40KT ON THE HIGHEST RIDGES EARLY ON AND THEN DIMINISHING.
SOUTHERN STREAM SYSTEM ARRIVES SAT NT WITH WARM ADVECTION AND WEAK
ISENTROPIC LIFT ALONG WITH UPPER LEVEL DIV...THE LATTER AIDED EARLY
ON VIA RRQ OF H3 JET. WARMING AT H85 ALONG WITH FREEZING SFC
TEMPERATURES IN THE NORTHERN WV MTNS SPELLS FREEZING RAIN WHEN
PRECIPITATION ARRIVES LATE SAT NT AND GOING INTO SUN. SYSTEM IS
EXODUS SUN NT/MON BUT IT REMAINS WARM ALOFT IN ITS WAKE.
NOT MUCH CHANGE NEEDED FOR HIGHS FRI. THIS KEEPS MORNING
TEMPERATURES LOW ENOUGH SO THAT...WITH THE STRONG WINDS EARLY
ON...WARRANT THE WIND CHILL ADVISORY UNTIL MID MORNING. LOWERED
LOWS A BIT SW PORTION OF AREA CLOSER TO MAV BASED ON HIGH BUILDING
IN FROM THAT DIRECTION. RAISED TEMPERATURES SAT ON TOWARD BUT NOT
ALL THE WAY TO THE LATEST MAV/MEX GUIDANCE. LOWS FREEZING OR LOWER
SHOULD BE LIMITED TO NORTHERN MOUNTAIN VALLEYS SAT NT FORWARD.
FREEZING RAIN IS POSSIBLE THIS AREA SAT NT AND MAY STILL BE A
CONCERN SUN NT WITH ANY LINGERING LIGHT RAIN OR DRIZZLE STILL
AROUND.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
RAISED TEMPERATURES MON...MON NT AND TUE BASED ON LATEST GUIDANCE
AND OVERALL PATTERN WITH SW FLOW AHEAD OF SYSTEM THAT ARRIVES TUE.
REST PREV...
BUSY NEARLY ZONAL FLOW CONTINUES THROUGH THE PERIOD. MAIN CONCERN IS
OPPORTUNITY OF WINTRY MIX AGAINST THE EASTERN MOUNTAINS WITH WARM
AIR ADVECTION ON BACKSIDE OF HIGH SATURDAY NIGHT INTO SUNDAY.
ALSO...A POTENTIALLY STRONG COLD FRONT MAY PASS EARLY TUESDAY.
TREND IN MODELS IS TO SLOW DOWN WARM AIR ADVECTION PRECIPITATION
THAT COMES IN FROM THE SOUTH SATURDAY NIGHT INTO SUNDAY. ALSO
HOWEVER...MOST OF THE MOISTURE REMAINS TO OUR SOUTH. I WENT SLIGHTLY
BELOW HPC POPS TO ACCOUNT FOR THIS TREND. HOWEVER...COLD AIR DAMMING
ALONG THE EAST SLOPES OF THE WV MOUNTAINS...IS SUPPORTIVE OF
PROSPECT FOR POSSIBLE FREEZING RAIN THROUGH EARLY SUNDAY...WHILE
MOST OF THE REMAINDER OF THE AREA HAS PLAIN RAIN /PERHAPS A LITTLE
MIX IN THE NORTHERN LOWLANDS/. SO I HAVE ADDED ICE CHANCES TO THE
WEATHER GRIDS FOR THE AFFECTED AREAS. TEMPERATURES IN GENERAL WILL
BE COMPLICATED SATURDAY NIGHT...THAT IS...NON DIURNAL FOR MANY AREAS
DUE TO WARM AIR ADVECTION.
NEXT FEATURE OF INTEREST IS A COLD FRONT THAT LOOKS TO PASS THROUGH
SOMETIME IN THE LATE MONDAY NIGHT THROUGH TUESDAY MORNING TIME
FRAME. WENT ALONG WITH MID CHANCE RANGE FOR POPS...WITH MAINLY RAIN
ON FRONT END TRANSITIONING TO UPSLOPE SNOW FOR MAINLY THE MOUNTAINS
TUESDAY NIGHT INTO WEDNESDAY.
WHILE OPERATIONAL GFS AND ECMWF GENERALLY AGREE WITH THIS
SCENARIO...RUN-TO-RUN CONSISTENCY IS NOT GREAT AND THERE IS A FAIR
AMOUNT OF SPREAD IN THE ENSEMBLES. NOT SURE HOW AMPLIFIED THE
ASSOCIATED INCOMING TROUGH WILL BE...AND THE DEGREE OF COLD AIR
ADVECTION BEHIND THE FRONT INTO MIDWEEK. THE ONLY CERTAIN THING WILL
BE A STRONG TEMPERATURE GRADIENT FROM THE GREAT LAKES IN THE
NORTH...TO THE OHIO VALLEY IN THE SOUTH.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ACROSS THE REGION TODAY...EXCEPT FOR
OCCASIONAL MVFR IN LIGHT SNOW SHOWERS THROUGH 22Z...MAINLY OVER
NORTHERN WV AND NORTHERN MOUNTAINS OF WV. GUSTY WNW WINDS WILL
CONTINUE TODAY...WITH GUSTS OF UP TO 30 KTS EXPECTED. HIGHER GUSTS
OF UP TO 40 KTS CAN BE EXPECTED OVER THE HIGHER TERRAIN. MODERATE
TO STRONG WESTERLY WINDS ALOFT.
AFTER 12Z FRIDAY...
NO SIGNIFICANT WEATHER EXPECTED AT THIS TIME.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 10 AM EST FRIDAY
FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/SL
NEAR TERM...SL/30
SHORT TERM...TRM
LONG TERM...MDP
AVIATION...
