Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 291725
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
125 PM EDT SUN MAR 29 2015

.SYNOPSIS...
HIGH PRESSURE EXITS EAST...ALLOWING A COLD FRONT TO SPREAD SHOWERS
ACROSS THE AREA THROUGH MONDAY MORNING. ADDITIONAL COLD FRONTS WILL
MOVE THROUGH THE OHIO VALLEY FOR THE UP COMING WORK WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
SFC SOUTHERLY FLOW...AND H850 SOUTHWEST FLOW BRINGS WARMER
TEMPERATURES TO THE REGION AHEAD OF AN INCOMING WARM/COLD FRONT
COMBO ASSOCIATED WITH A SFC LOW PRESSURE SYSTEM PASSING ACROSS THE
GREAT LAKES REGION TONIGHT. H500 CHARTS INDICATE THAT
MOST OF THE ENERGY FROM THE UPPER TROUGH PASSES NORTH ACROSS PA.

CLOUDS WILL INCREASE FROM WEST TO EAST OVERNIGHT WITH CHANCES FOR
RAIN SHOWERS INCREASING OVER SOUTHEAST OH BY 03Z...SPREADING EAST
ACROSS WV OVERNIGHT. BY 12Z THE BULK OF PCPN SHOULD BE ALONG THE
EASTERN MOUNTAINS AS THE COLD FRONT EXITS EAST. PERIODS OF LIGHT TO
MODERATE RAIN CAN BE EXPECTED WITH NO FLOODING ANTICIPATED AT THIS
TIME. INCREASED POPS TO LIKELY TO CATEGORICAL PER SREF
PROBABILITIES OF MEASURABLE RAIN EXCEEDING 80 PERCENT...AND GOOD
TIMING CONSENSUS IN QPF FIELDS FROM OTHER MODELS. AS THE COLD
FRONT APPROACHES...THE PRESSURE GRADIENT WILL TIGHTEN UP.
OCCASIONAL GUSTY WINDS ALONG SHOWERS WILL BE POSSIBLE. THE NAM
MODEL SUPPORTS THIS REASONING SHOWING 50 TO 60 KNOTS AT H850.
BELIEVE ANY SHOWER COULD MIX DOWN A FRACTION OF THESE WINDS ALONG
THEIR PATH.

MODELS SUGGEST H850 FREEZING LEVEL LINGERING ACROSS THE NORTHERN
THIRD OF THE CWA...SUGGESTING TEMPERATURES WILL NOT WARM MUCH UNDER
SOUTHWEST FLOW. COLDER AIR FILTERS IN BEHIND THE COLD
FRONT...CAPABLE TO CHANGE RAIN SHOWERS TO LIGHT SNOW OR MIX OVER THE
NORTHEAST MOUNTAINS LATE OVERNIGHT TONIGHT INTO EARLY MONDAY
MORNING.


&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
PATTERN CONTINUES TO UNDERGO CHANGE THIS PERIOD FROM A DEEP
EASTERN UPPER TROUGH AND WESTERN UPPER RIDGE...TO A MORE ZONAL
TYPE FLOW ALOFT. ONE LAST CLIPPER LIKE SYSTEM DROPS SOUTHEAST
LATER TUESDAY AND TUESDAY NIGHT JUST NORTH AND EAST OF OUR
AREA...BRINGING A WEAK FRONT ACROSS TUESDAY NIGHT. WHILE MOISTURE
IS AVAILABLE INTO THIS SYSTEM...THE ISENTROPIC LIFT AND WARM
ADVECTION NORTH OF THE TRACK OF THE SURFACE LOW WILL KEEP MOST OF
THE ATTENDING LIGHT SHOWERS WITH THE SYSTEM IN THE NORTH. MODELS
IN REASONABLE AGREEMENT WITH THIS SYSTEM. HIGH PRESSURE FOLLOWS
WEDNESDAY BEFORE THE REAL PATTERN CHANGE TAKES EFFECT. UP TO THIS
POINT TEMPERATURES WILL UNDERGO A WARMING TREND...EVEN BEHIND THE
WEAK FRONT...AS AIR BECOMES INCREASINGLY PACIFIC IN NATURE.

BY THURSDAY...THE FIRST IN A SERIES OF PACIFIC SYSTEMS ROLLS ACROSS
THE NATION WITH ZONAL FLOW ALOFT TAKING CONTROL. IN THIS
PATTERN...SURFACE HIGH PRESSURE BECOMES ANCHORED OFF THE SOUTHEAST
COAST OF THE NATION...WITH THE GULF OF MEXICO OPENING UP WITH
SOUTHERLY FLOW AHEAD OF THE SYSTEM. WHILE THE EXACT STRENGTH AND
TRACK OF THE SYSTEM IS QUESTIONABLE...IT WILL BRING A BETTER
CHANCE FOR SHOWERS THURSDAY...AND PERHAPS A THUNDERSTORM...WITH
QUITE WARM TEMPERATURES.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
GENERALLY FOLLOWED HPC WHICH GIVES A NOD TO A MORE AMPLIFIED
SOLUTION FOR LATE WEEK AND INTO EASTER WEEKEND. WHILE A SIGNIFICANT
WARMUP IS EXPECTED MID TO LATE WEEK...IT MAY BE HAMPERED BY SHOWERS
ON LATE THURSDAY AND INTO EARLY FRIDAY AS A PESKY DISTURBANCE COMES
OUT OF THE S STREAM BEFORE HEIGHTS CAN BUILD. THE MAIN SYSTEM WILL
BE FRIDAY EVENING. A DEEPENING LOW IS EXPECTED TO TRACK INTO THE
GREAT LAKES AS A S/W TROF GOES NEGATIVE TILT. THE RESULTING STRONG
BAROCLINIC ZONE AND LLJ MAY PRODUCE A HEALTHY LINE OF CONVECTIVE
SHOWERS WITH IT AND THIS WILL NEED TO BE MONITORED IN THE COMING
DAYS. THE COLD FRONT QUICKLY SWEEPS THRU FRIDAY NIGHT. THE WEEKEND
IS SHAPING UP TO BE RATHER COOL...ESPECIALLY ON SUNDAY WITH EVEN THE
POTENTIAL FOR MORE SNOW SHOWERS SATURDAY NIGHT AND EARLY SUNDAY.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL CONTINUE AS A HIGH PRESSURE EXITS EAST OF THE
MOUNTAINS THROUGH THIS EVENING. A COLD FRONT WILL APPROACH FROM
THE WEST TONIGHT TO INCREASE CLOUDS AND RAIN SHOWERS FROM WEST TO
EAST TONIGHT. THE BULK OF THE PCPN IS EXPECTED OVERNIGHT.
TEMPERATURES ACROSS THE NORTHEAST MOUNTAINS WILL BE BELOW
FREEZING...SO EXPECT PCPN TO TRANSITION INTO SNOW OR A MIX PCPN
DURING THE PREDAWN HOURS.

THEREFORE...MVFR CONDITIONS ARE EXPECTED ALONG THE INITIAL SHOWERS
REACHING SOUTHEAST OH...PKB AND HTS AROUND 03-05Z. THEN...SHOWERS
AND ASSOCIATED MVFR CEILINGS AND VISIBILITIES WILL SPREAD EAST TO
AFFECT THE REST OF SITES. IFR CEILINGS CAN BE EXPECTED OVER HIGHER
TERRAIN INCLUDING BKW AFTER 08Z. SHOWER RELATED IFR CONDITIONS CAN
NOT BE RULED OUT IF SHOWERS BECOME MODERATE TO HEAVY FOR SHORT
PERIODS OF TIMES.

LIGHT SOUTHERLY WINDS WILL BECOME GENTLE TO MODERATE TONIGHT AHEAD
AND ALONG THE COLD FRONT. MODELS SUGGEST H850 WINDS OF 50 TO 60
KNOTS WILL ACCOMPANY THE FRONT AND A PORTION OF THESE WINDS CAN BE
MIXED DOWN BY ANY SHOWER.

COLD FRONT SHOULD BE EXITING THE EASTERN MOUNTAINS BY 13-14Z
MONDAY MORNING...WITH IMPROVING CONDITIONS SPREADING FROM WEST TO
EAST BY MID MORNING TO NOON.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: HIGH.

ALTERNATE SCENARIOS: TIMING OF CLOUDS AND PRECIP LATER TONIGHT MAY
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
EDT 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
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  H    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    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z MONDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED AT THIS TIME.

&&

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

&&

$$
SYNOPSIS...JB/ARJ/30
NEAR TERM...ARJ
SHORT TERM...JMV
LONG TERM...30
AVIATION...ARJ








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