467
FXUS61 KRLX 182023
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
415 PM EDT THU MAR 18 2010
SYNOPSIS
HIGH PRESSURE IN CONTROL THROUGH SATURDAY. SHOWERY COLD FRONT PASSES
SUNDAY NIGHT. COOLER MONDAY...BUT TEMPERATURES MODERATE THROUGH THE
MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH FRIDAY/
A HIGH PRESSURE SYSTEM WILL PROVIDE DRY WEATHER TONIGHT AND FRIDAY.
GENERALLY WENT BELOW MOS GUIDANCE FOR LOWS TONIGHT AS MODELS HAVE
BEEN TOO WARM IN AREAS THAT HAD GOOD RADIATION CONDITIONS THE LAST
SEVERAL NIGHTS.
SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/
NO SIGNIFICANT CHANGES TO THIS TIME FRAME. THINKING JUST SOME
CIRRUS AND SMALL CU DEVELOPING SATURDAY...WITH MID DECK POSSIBLE
LATE IN THE WEST. RAISED MAXIMUM TEMPERATURE SLIGHTLY. STILL LIKE
THE SLIGHT CHANCE OF SHOWERS REACHING SE OHIO SATURDAY NIGHT WITH
WEAK VORT MAX RIDING NE THRU OHIO...S OF THE FRONTAL ZONE OVER
NORTHERN OHIO. TRICKY MINIMUM TEMPERATURES SATURDAY NIGHT...WENT A
BIT COLDER IN SRN VALLEYS SUCH AS NR CLINTWOOD AND
PINEVILLE...COMPARED TO SE OHIO...THINKING LESS CLOUDS AND WIND.
LONG TERM /SUNDAY THROUGH THURSDAY/
MOST NOTICEABLE TREND IN MODELS IS TO FINALLY COME INTO BIG PICTURE
AGREEMENT WITH OUR NEXT SYSTEM...BY CUTTING OFF AND MAINTAINING AN
UPPER LOW. THIS SLOWS DOWN THE PROGRESS OF THE ATTENDING LOW
PRESSURE SYSTEM. ALSO...THE SURFACE LOW TRACK IS NOW ROUGHLY UP THE
OHIO VALLEY. EXPECTING COLD FRONTAL PASSAGE TO NOW OCCUR MORE INTO
SUNDAY NIGHT INSTEAD OF SUNDAY...AND PERHAPS EVEN STILL EXITING THE
MOUNTAINS EARLY MONDAY MORNING. PEAK POPS REMAIN HIGH /70S/ BUT
NEEDED TO BE SHIFTED LATER BY A GOOD 6-10 HOURS. ONCE FRONTAL TIMING
CAN BE SOLIDIFIED...POPS WILL PROBABLY BE REFINED HIGHER INTO
CATEGORICAL.
WITH SLOWER TIMING OF FRONT...TEMPERATURES WERE OF COURSE ALSO
DRAMATICALLY IMPACTED FOR SUNDAY...WITH ANOTHER DAY IN THE WARM
SECTOR. ALSO...AXIS OF ELEVATED INSTABILITY IS BECOMING MORE
APPARENT WITH EACH SET OF MODELS ALONG THE NOW NEGATIVELY TILTED
FRONT...THOUGH STILL IS QUITE MARGINAL. WENT AHEAD WITH A CHANCE OF
THUNDER DURING FRONTAL PASSAGE...TO ACCOMPANY LIKELIHOOD OF SHOWERS.
COOLING BEHIND THE SYSTEM ALSO APPEARS MORE MUTED WITH EACH RUN. AS
COLD CORE OF UPPER LOW PASSES OVER MONDAY...EXPECTING INSTABILITY
SHOWERS TO LINGER...ESPECIALLY NORTHERN ZONES. UPSLOPE FLOW WILL
EVEN KEEPS SHOWERS INTO MONDAY NIGHT IN THE MOUNTAINS.
HOWEVER...925MB TEMPERATURES BARELY REACH AROUND 0 CELSIUS AT
WORST...DESPITE 1000-500MB THICKNESSES BRIEFLY DIPPING BELOW 540MB
/THAT RULE OF THUMB BECOMES LESS RELEVANT HEADING INTO SPRING/. SO
PROSPECTS FOR SNOW SHOWERS TO MIX IN WITH THE RAIN LOOK LIMITED.
BEST CHANCE OF SOME SNOW SHOWERS WOULD BE INTO MONDAY NIGHT IN THE
NORTHERN MOUNTAINS...BUT NO ACCUMULATION EXPECTED AT THIS TIME.
SURFACE HIGH PRESSURE RIDGE PASSES LATE TUESDAY INTO
WEDNESDAY...WITH WARM AIR ADVECTION ALOFT...AND THUS DAYTIME
TEMPERATURES HEAD BACK ABOVE NORMAL DURING MIDWEEK. GFS APPEARS TOO
FAST WITH ITS COLD FRONT ARRIVING THURSDAY...PREFER THE SLOWER
SCENARIO OF ECMWF WITH UPSTREAM CUTOFF LOW CONSIDERING TIME OF YEAR.
REGARDLESS...INCREASING MOISTURE IN THE SOUTHWEST FLOW WILL ALSO
INCREASE RAIN CHANCES THURSDAY ONWARD.
AVIATION /20Z THURSDAY THROUGH TUESDAY/
A HIGH PRESSURE SYSTEM WILL PROVIDE VFR CONDITIONS THROUGH THE
PERIOD.
AFTER 18Z FRIDAY...
BRIEF IFR POSSIBLE IN SHOWERS/ISOLATED THUNDERSTORMS SUNDAY.
RLX WATCHES/WARNINGS/ADVISORIES
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
SYNOPSIS...KTB/MDP/RPY
NEAR TERM...RPY
SHORT TERM...KTB
LONG TERM...MDP
AVIATION...RPY
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