Area Forecast Discussion
Issued by NWS Wilmington, OH

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000
FXUS61 KILN 210244
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
1044 PM EDT WED AUG 20 2014

.SYNOPSIS...
A FRONTAL ZONE WILL SETTLE INTO THE OHIO VALLEY TONIGHT. THIS
FRONT WILL GRADUALLY LIFT NORTHEAST INTO THE GREAT LAKES THROUGH
THE WEEKEND. DISTURBANCES WILL INTERACT WITH A MOIST AIRMASS TO
PRODUCE SHOWERS AND THUNDERSTORMS AT TIMES THROUGH THE PERIOD.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
DRY CONDITIONS WILL START OUT THE NEAR TERM. A FEW ISOLATED
SHOWERS ARE DEVELOPING OVER NW OHIO AND ALSO SE INDIANA. THE HI
RES MODELS ARE PICKING UP ON THIS RATHER WELL AND SHOWING
ADDITIONAL DEVELOPMENT INTO NW PORTIONS OF THE FA DURING THE
OVERNIGHT HOURS. INCREASED PRECIPITATION CHANCES IN THIS AREA
OVERNIGHT HOWEVER EXPECT MOST OF THE MORE WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY TO HOLD OFF UNTIL THE EARLY DAYTIME HOURS ON
THURSDAY.

TEMPERATURES HAVE DROPPED OFF INTO THE 60S ACROSS PORTIONS OF THE
AREA. UPPER 60S ARE MORE WIDESPREAD ACROSS NE PORTIONS OF THE FA
WHERE THERE IS LESS CLOUD COVER. THE RATE OF COOLING WILL SLOW
OVERNIGHT AS ADDITIONAL CLOUDS MOVE INTO THE AREA HOWEVER EXPECT
MOST LOCATIONS TO DROP DOWN INTO THE 60S OVERNIGHT.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
THERE IS A LARGE VARIATION IN MODEL SOLUTIONS FOR THURSDAY. PREFER
A NAM/CMC REGIONAL/HIRES-WRF SOLUTION WHICH DROPS H5 ENERGY INTO
THE REGION EARLY THURSDAY MORNING IN THE NW FLOW. THEY PUSH THE
BEST PCPN CHANCE ACROSS THE REGION DURING THE MORNING...AND EXIT
IT OUT OF THE EAST DURING THE AFTN.

THURSDAY NIGHT BETTER FORCING SHIFTS TO NRN OHIO AS CONVERGENCE
ALONG A LIFTING WARM FRONT MOVES ALSO. PUT HIGH CHANCE POPS IN THE
NORTHERN COUNTIES WITH DECREASING POPS DOWN TO THE SW.

ON FRIDAY...ADDITIONAL H5 ENERGY TOPS THE RIDGE AND DROPS SE
ACROSS THE REGION. THIS WILL HELP DEVELOP DAYTIME CONVECTION...BUT
CENTRAL OHIO WILL HAVE THE BEST CHANCE AT SEEING CONVECTION AS IT
IS CLOSER TO THE WARM FRONT.

CONVECTION TOMORROW WILL COMPLICATE THE HIGH TEMPERATURE FORECAST.
ONLY WENT LOWER 80S IN THE NW COUNTIES SINCE THE CONVECTION SHOULD
LIMIT HEATING THERE. SOUTHERN COUNTIES SHOULD BE ABLE TO MAKE THE
MID TO UPPER 80S. AFTER DROPPING DOWN TO ONLY AROUND 70 THURSDAY
NIGHT...FRIDAY IS LOOKING LIKE A HOT AND HUMID DAY. OHIO RIVER
COUNTIES SHOULD SEE TEMPERATURES PUSH INTO THE LOWER 90S WITH
DEWPOINTS IN THE LOWER 70S. THIS WILL PUSH HEAT INDICES OVER 100.
WILL CONTINUE TO HIGHLIGHT THE THREAT IN THE HWO.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AT 12Z ON SATURDAY...THE 20.12Z ECMWF AND GFS ARE VERY GOOD
AGREEMENT ON THE LARGE SCALE PATTERN WITH AN AMPLIFIED FLOW PATTERN
OVER THE LOWER 48. A DEEP CLOSED LOW SHOULD BE OVER ID/MT WITH A
STRONG SUBTROPICAL RIDGE EXTENDING NORTHEAST FROM A 593DM HIGH OVER
ALABAMA. ANOMALOUS MOISTURE WILL STILL BE IN PLACE WITH PWAT FROM
1.5 TO 2.0 STANDARD DEVIATIONS ABOVE CLIMO. THROUGH THE WEEKEND THE
STRONG CLOSED LOW WILL SWING NORTHEAST INTO THE NRN HIGH PLAINS AND
EVENTUALLY INTO SASK...WHILE THE RIDGE EXPANDS NORTHEASTWARD INTO
TN/ARK. DESPITE WEAK FORCING...CONTINUED NORTHERLY/NORTHWESTERLY
FLOW AROUND THE RIDGE...THE PRESENCE OF A WEAK SURFACE TROUGH...AND
ANOMALOUS MOISTURE SHOULD CONTINUE TO ALLOW FOR STRONG DAYTIME
INSTBY BOTH SAT AND SUN. THE POTENTIAL FOR ONE MORE CLUSTERS OF SSE
PROPAGATING STORM CLUSTERS WILL CONTINUE THROUGH THE WEEKEND. GIVEN
THE MAGNITUDE OF INSTBY...EVEN WITH WEAKENING FLOW WITH TIME...THERE
COULD BE STRONG/SEVERE STORM THREAT ON EITHER OF THESE DAYS IF A
ORGANIZED COLD POOL COULD FORM. GETTING INTO MONDAY-TUESDAY...THE
RIDGE CONTINUES TO BUILD WITH HEAT/HUMIDITY. FLOW BECOMES VERY LIGHT
THROUGH THE BULK OF THE TROPOSPHERE AND IT BECOMES QUESTIONABLE IF
COVERAGE OF DAYTIME/EVE STORMS WARRANTS MENTION. RIGHT NOW HAVE RUN
15-25% RAIN CHANCES BOTH OF THESE DAYS...AND THAT MAY BE TOO HIGH.
INTO WEDNESDAY...SOME HINTS OF HEIGHT FALLS WHICH MAY ALLOW A LITTLE
STRONGER FLOW OR A WEAK SHORTWAVE TROUGH TO CROSS THE GREAT LAKES.
SO A BETTER STORM THREAT THEN...HOWEVER AT THIS TIME RANGE THIS IS A
VERY LOW CONFIDENCE FORECAST GIVEN CONDITIONAL NATURE OF THE RIDGE
BUCKLING.

SO ALL IN ALL...HAVE TENDED TO FOCUS RAIN CHANCES NEAR PEAK HEATING
INTO THE EVENING AND ALLOW FOR SOME DRY NIGHTS/EARLY MORNINGS. FLY
IN OINTMENT WILL BE ANY FORWARD PROPAGATING MCS THAT SURVIVES
THROUGH THE NIGHT...ORIGINATING TO OUR NORTHWEST  AND FALLING DOWN
NNWLY FLOW EITHER SATURDAY MORNING OR SUNDAY MORNING. LOW CONFIDENCE
STORM CHANCE...BUT HIGH CONFIDENCE WARM/HUMID PATTERN IS THE STORY
FOR THE SAT-WED TIMEFRAME.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
SHOWERS AND THUNDERSTORMS HAVE EXITED THE AREA AND EXPECT DRY
CONDITIONS ACROSS THE TAF SITES THIS EVENING AND FOR MOST OF THE
OVERNIGHT HOURS. A DISTURBANCE WILL APPROACH THE AREA LATE IN THE
OVERNIGHT HOURS AND INTO THE DAYTIME MORNING HOURS ON THURSDAY.
HAVE A VCTS MENTION AT ALL TAF SITES FOR AWHILE DURING THIS TIME.
ADDED IN A TEMPO TSRA MENTION AT ALL AREA TAF SITES EXCEPT KCVG
AND KLUK.

THERE IS SOME QUESTION ON HOW LONG THE SHOWERS AND THUNDERSTORMS
WILL LINGER INTO THE AFTERNOON AND IF THERE WILL BE ADDITIONAL
DEVELOPMENT. EXPECT ANY ADDITIONAL DEVELOPMENT TO EXIT THE TAF
SITES BY THE END OF THE TAF PERIOD.

ADDITIONAL PRECIPITATION WILL START TO WORK INTO THE KCVG TAF AT
THE END OF THAT TAF PERIOD DUE TO THE LONGER TAF PERIOD. IN
ADDITION SOME FOG WILL BE POSSIBLE AT KCVG AND KLUK OVERNIGHT DUE
TO THE PREVIOUS RAINFALL AT THOSE LOCATIONS.

OUTLOOK...THUNDERSTORMS POSSIBLE THURSDAY EVENING THROUGH
SUNDAY.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.

&&

$$
SYNOPSIS...SITES/SNYDER
NEAR TERM...NOVAK
SHORT TERM...SITES
LONG TERM...BINAU
AVIATION...NOVAK






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