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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 152327
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
727 PM EDT TUE APR 15 2014

.SYNOPSIS...
SURFACE HIGH PRESSURE WILL MOVE OVER THE OHIO VALLEY
TONIGHT...BEGINNING TO MOVE EAST OF THE REGION TOMORROW. BY
THURSDAY...SOUTHERLY WINDS WILL ALLOW FOR A WARMING OF
TEMPERATURES THROUGH FRIDAY...WITH RAIN POSSIBLE BY FRIDAY
AFTERNOON.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
DEEP MOISTURE HAS MOVED WELL EAST OF THE REGION...WITH THE ILN CWA
IN A REGIME OF NORTHWESTERLY FLOW...AS SURFACE HIGH PRESSURE
BEGINS TO BUILD IN FROM THE WEST. A WELL-MIXED BOUNDARY LAYER HAS
LED TO THE DEVELOPMENT OF SOME INSTABILITY-DRIVEN CUMULUS (WITH
FLURRIES EVIDENT ON RADAR FOR MOST OF THE AFTERNOON).
HOWEVER...THIS MOISTURE IS SHALLOW...AND THIS ACTIVITY SHOULD
DISSIPATE QUICKLY AFTER THE DIURNAL MAXIMUM HAS BEEN PASSED.
CLOUDS ARE NOT EXPECTED TO LAST VERY LONG TONIGHT...WITH MOSTLY
CLEAR TO CLEAR SKIES EXPECTED BY MID EVENING.

THE CENTER OF THE HIGH WILL BE MOVING OVER THE MIDDLE OHIO VALLEY
AT AROUND 06Z...PROVIDING A FAVORABLE SCENARIO FOR RADIATIONAL
COOLING. CLEAR SKIES AND LIGHT WINDS WILL ENHANCE THE POTENTIAL
FROM THE COOL AIR MASS ALREADY IN PLACE...LEADING TO A LOW
TEMPERATURE FORECAST THAT COMES VERY CLOSE TO RECORD VALUES.
RECORD LOWS FOR APRIL 16 ARE AS FOLLOWS:

CMH: 22 DEGREES IN 1962/1935
CVG: 24 DEGREES IN 1875
DAY: 23 DEGREES IN 1962

THE MIN TEMPERATURE GRID IS NEAR THE LOW END OF THE MODEL
SPREAD...EASILY SUPPORTING A CONTINUANCE OF THE FREEZE WARNING FOR
THE AREAS WHERE THAT PROGRAM IS ACTIVE...AND A FORECAST OF
WIDESPREAD FROST THROUGHOUT THE ILN CWA.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
-- Changed Discussion --
ON WEDNESDAY...THE CENTER OF THE SURFACE HIGH WILL CONTINUE TO
MOVE AWAY FROM THE ILN CWA...IN A GENERALLY-NORTHEAST DIRECTION
TOWARD NEW ENGLAND. WITH SURFACE LOW PRESSURE OVER THE NORTHERN
PLAINS...THIS WILL SUPPORT A SURFACE FLOW PATTERN THAT ALLOWS
WINDS TO SHIFT TO THE SOUTHEAST ON WEDNESDAY...AND TO THE SOUTH ON
THURSDAY.

THE WARM ADVECTION THROUGH THE LOWEST FEW THOUSAND FEET WILL NOT
BE ALL THAT STRONG ON WEDNESDAY...BUT THE AIR MASS WILL BE
CHANGING ENOUGH TO WARRANT A SIGNIFICANT BUMP IN SURFACE
TEMPERATURES...ESPECIALLY WITH SUN AND MIXING (THROUGH AROUND
850MB) EXPECTED. ON WEDNESDAY NIGHT...THOUGH WARM ADVECTION NEAR
900MB WILL INCREASE...CLEAR SKIES WILL ALLOW FOR RELATIVELY
FAVORABLE RADIATIONAL COOLING. FREEZING CONDITIONS APPEAR
GENERALLY UNLIKELY...AND FROST POTENTIAL IS IN QUESTION...WITH DRY
AIR AND SOME WIND REMAINING IN PLACE. SOME FROST WAS ADDED TO THE
GRIDS...BUT CONFIDENCE IS NOT YET HIGH ENOUGH TO INCLUDE IN THE
HWO OR CONSIDER ISSUING A HEADLINE.

THE SOUTHERLY FLOW ON THURSDAY WILL SUPPORT WARMER
CONDITIONS...WITH THE ENTIRE CWA GETTING INTO THE 60S. THOUGH A
FEW CUMULUS CLOUDS ARE NOT OUT OF THE QUESTION...IN GENERAL ONLY
SOME PATCHES OR STREAKS OF CIRRUS/CIRROSTRATUS ARE EXPECTED. LATE
ON THURSDAY NIGHT...A MORE SIGNIFICANT INCREASE IN CLOUD COVER IS
EXPECTED. MOISTURE ADVECTION OVER THE OHIO VALLEY WILL PICK UP IN
STRENGTH...IN ADVANCE OF A RATHER LARGE TROUGH THAT WILL BE MOVING
TO THE EAST OUT OF THE MISSISSIPPI VALLEY. HOWEVER...CHANCES FOR
PRECIPITATION APPEAR LIKELY TO WAIT UNTIL FRIDAY MORNING.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
DRY CONDITIONS AT THE START OF THE LONG TERM WILL BE SHORT LIVED.
AN UPPER LEVEL DISTURBANCE WILL WORK INTO THE AREA ON FRIDAY AND
INTO FRIDAY NIGHT.  THERE IS SOME LIMITED INSTABILITY DURING THE DAY
AND THEREFORE HAVE A CHANCE OF THUNDER IN THE FORECAST AS WELL.
PRECIPITATION WILL TAPER OFF BY SATURDAY MORNING.

HIGH PRESSURE AND DRY CONDITIONS WILL BE IN PLACE FOR THE REMAINDER
OF THE WEEKEND.  THE MODELS ARE IN AGREEMENT WITH BRINGING ANOTHER
SYSTEM INTO THE AREA MONDAY INTO MONDAY NIGHT.  THE ECMWF IS MORE
ROBUST WITH THIS SYSTEM THAN THE GFS.  AT THIS POINT WENT WITH A
MODEL BLEND HOWEVER LIMITED PRECIPITATION CHANCES TO THE CHANCE
CATEGORY DUE TO UNCERTAINTY AND MODEL VARIABILITY.  THERE IS AGAIN
SOME LIMITED INSTABILITY DURING THE DAY ON MONDAY AND HAVE A CHANCE
OF THUNDER MENTIONED.  THIS SYSTEM WILL MOVE OUT OF THE AREA TUESDAY
MORNING.  HIGH PRESSURE WILL THEN MOVE INTO THE REGION BY THE END OF
THE LONG TERM.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. STRATOCUMULUS WILL
DISSIPATE EARLY IN THE TAF PERIOD AND WINDS WILL DIMINISH. HIGH
PRESSURE MOVING ACROSS THE REGION WILL RESULT IN LIGHT AND
VARIABLE WINDS OVERNIGHT BECOMING SOUTHEAST ON WEDNESDAY. ONLY
ADDITIONAL CLOUDS WILL BE SOME THIN CIRRUS.

OUTLOOK...MVFR CEILINGS POSSIBLE FRIDAY INTO FRIDAY NIGHT.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FREEZE WARNING UNTIL NOON EDT WEDNESDAY FOR OHZ077>082-088.
KY...FREEZE WARNING UNTIL NOON EDT WEDNESDAY FOR KYZ089>100.
IN...FREEZE WARNING UNTIL NOON EDT WEDNESDAY FOR INZ073>075-080.

&&

$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...NOVAK
AVIATION...