-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 072345
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
645 PM EST FRI MAR 7 2014

.SYNOPSIS...
HIGH PRESSURE WILL MOVE SOUTHEAST OF THE REGION OVERNIGHT.
A WEAK COLD FRONT WILL BRING A CHANCE OF PRECIPITATION TO THE
REGION SATURDAY INTO SATURDAY NIGHT. HIGH PRESSURE WILL BUILD BACK
INTO THE AREA FOR SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --
EVENING UPDATE TO THE FORECAST HAD MINIMAL CHANGE ON MOST OF THE
PARAMETERS BUT A BIT OF A SWING IN DEWPOINT FORECAST INTO TOMORROW
AFTERNOON. OBSERVATIONS WERE SHOWING FAIRLY UNIFORM VALUES WITHIN
2-3 DEG OF EACH OTHER ACROSS CWA TO CONTINUE UNTIL A FROPA
TOMORROW. SHAVED A LITTLE OFF OF THE CLOUD COVER WHICH SHOULD NOT
HAVE ANY EFFECT ON ANY FORECAST OTHER THAN AESTHETICS.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
MODELS CONTINUE TO STRUGGLE IN TERMS OF THE AMOUNT OF FORCING THAT
WILL ACCOMPANY A WEAK COLD FRONT WHICH WILL MOVE FROM NORTHWEST TO
SOUTHEAST THROUGH OUR REGION SATURDAY INTO SATURDAY NIGHT. AS
SUCH...HAVE STILL KEPT THE THREAT FOR PCPN IN THE CHANCE CATEGORY.
THE NAM IS THE MOST AGGRESSIVE...AND TO THE LESSER EXTENT...THE
ECMWF...FOR PCPN DEVELOPMENT ACRS OUR SRN ZONES SATURDAY EVENING
AS PERHAPS A WEAK RIPPLE ALONG THE FRONT MOVES ALONG THE SOUTHEAST
MOVING FRONTAL ZONE. TEMPERATURES ON SATURDAY WILL AGAIN BE MILD
BUT COOLER ACRS THE NORTH WHERE THE FRONT WILL ARRIVE FIRST.
HIGHS WILL RANGE FROM THE LOWER 40S NW TO THE MID 50S SOUTHEAST.
CAA BEHIND THE FRONT WILL ALLOW A BRIEF PERIOD OF SNOW TO MIX IN
WITH RAIN BEFORE ENDING ACRS OUR AREA...WITH LITTLE TO NO SNOW
ACCUMULATION EXPECTED. SKIES WILL CLEAR FROM NW TO SE LATE SATURDAY
NIGHT IN THE WAKE OF THE FRONT. LOWS SATURDAY NIGHT WILL RANGE
FROM THE LOWER 20S NW TO THE LOWER 30S SE.

FOR SUNDAY...A RIDGE OF HIGH PRESSURE WILL PUSH SOUTHEAST ACROSS
THE LOWER GREAT LAKES AND THE OHIO VALLEY. MOSTLY SUNNY SKIES ARE
EXPECTED. WITH SUNSHINE...TEMPERATURES WILL RANGE FROM THE LOWER
40S NORTH TO THE UPPER 40S SOUTH.

FOR SUNDAY NIGHT...SURFACE RIDGE CONTINUES SOUTHEAST WHILE SOME
CLIPPER SYSTEMS PUSH EAST SOUTHEAST NEAR THE NRN GREAT LAKES. THIS
WILL ALLOW SOME HIGHER CLOUDS TO INCREASE ACROSS THE NORTH WHILE
INCREASING THE SURFACE PRESSURE GRADIENT. THIS WILL PREVENT FROM
LOWS GETTING TOO COLD WHICH SHOULD RANGE FROM THE UPPER 20S TO THE
LOWER 30S.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
THE WEATHER PATTERN THROUGH THE EXTENDED FORECAST PERIOD WILL BE
CHARACTERIZED BY GENERALLY-WNW FLOW ALOFT...WITH THE BULK OF THE
NORTHERN STREAM REMAINING JUST NORTH OF THE OHIO VALLEY THROUGH
TUESDAY. AT THE SURFACE...THERE WILL BE ALTERNATING BRIEF PERIODS OF
HIGH AND LOW PRESSURE...WITH THE LOW TRACKS MAINLY FOCUSED NORTH OF
THE REGION UNTIL MID-WEEK. THE GREATEST FORECAST COMPLICATION WILL
BE ON WEDNESDAY...AS SURFACE LOW PRESSURE PASSES THROUGH THE
TENNESSEE AND SOUTHERN OHIO VALLEY REGIONS.

EARLY IN THE WEEK...ALL SIGNS POINT TO A CONTINUED WARMING
TREND...WITH SPRAWLING SURFACE HIGH PRESSURE OVER THE SOUTHERN
STATES. THIS WILL REACH FAR ENOUGH NORTH TO INFLUENCE THE OHIO
VALLEY ON TUESDAY...WITH A SHARP FRONTAL TEMPERATURE GRADIENT
EXPECTED TO BE PUSHED TO THE NORTHERN BORDER OF THE ILN CWA
(POTENTIALLY OUT OF THE CWA ENTIRELY). TEMPERATURES IN THE LOWER 60S
APPEAR POSSIBLE FOR THE SOUTHERN CWA ON BOTH DAYS...WITH SKIES
IMPACTED MAINLY BY HIGH CLOUDS SPILLING IN FROM THE NORTH. THE GFS
HAS CONTINUED TO DEPICT A MORE ACTIVE NORTHERN STREAM DURING THIS
TIME FRAME...COMING CLOSE TO ALLOWING PRECIPITATION INTO THE REGION
ON MONDAY OR MONDAY NIGHT. WITH NO SUPPORT FROM THE OTHER
MODELS...THIS IDEA WILL CONTINUE TO BE DISCOUNTED.

PRECIPITATION NOW APPEARS FAIRLY CERTAIN FOR THE ILN CWA AT SOME
POINT IN THE TUESDAY NIGHT THROUGH THURSDAY TIME FRAME...WITH THE
12Z MODEL RUNS TODAY FOCUSING PRIMARILY ON WEDNESDAY. HOWEVER...THIS
TIMING HAS NOT BEEN OVERLY CONSISTENT DURING THE PAST FEW RUN-TO-RUN
CYCLES. THE GREATEST CONCERN IN TERMS OF FORECAST CONFIDENCE IS THE
CHALLENGE OF DETERMINING HOW THE VARIOUS SHORTWAVES WILL INTERACT
WITH EACH OTHER AS THEY MOVE INTO THE EASTERN HALF OF THE COUNTRY.
THE RELATIVELY-ACTIVE NORTHERN STREAM IS SURE TO SEND A SHORTWAVE
THROUGH THE REGION...BUT WHETHER OR NOT IT FULLY INTERACTS WITH
ANOTHER SHORTWAVE MOVING ENE OUT OF TEXAS IS WHAT WILL HELP
DETERMINE THE EVENTUAL STRENGTH AND PLACEMENT OF THE SURFACE LOW
DEVELOPMENT. THIS WILL NOT ONLY HAVE AN IMPACT ON PRECIPITATION
AMOUNTS...BUT ALSO THE WEATHER TYPES AND TEMPERATURES...WITH THE
TRANSITION FROM RAIN TO SNOW EXPECTED TO CROSS THROUGH THE REGION.
GIVEN THE TIMING CONCERNS...TEMPERATURES WERE RUN AS DIURNAL...BUT
THE EVENTUAL EVOLUTION OF THE SYSTEM MAY REQUIRE THIS TO BE CHANGED.

ONE THING THAT DOES APPEAR FAIRLY CERTAIN IS THAT A SURFACE FRONT
WILL PASS SOUTH THROUGH THE AREA ON TUESDAY NIGHT THROUGH WEDNESDAY
MORNING...BRINGING A RETURN TO COOLER CONDITION HEADING INTO THE
SECOND HALF OF THE WEEK. BROAD SURFACE HIGH PRESSURE WILL SPREAD
ACROSS THE SOUTHEASTERN STATES THROUGH THE END OF THE
WEEK...EXTENDING FAR ENOUGH INTO THE OHIO VALLEY TO KEEP CONDITIONS
DRY THROUGH FRIDAY.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
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HIGH PRESSURE WILL GRADUALLY GIVE WAY TO SOUTHWEST FLOW TONIGHT AS
IT DEPARTS AHEAD OF A COLD FRONT. HIGH CLOUDS WILL STREAM IN
OVERNIGHT FROM THE WEST. FROPA WILL BE AROUND 20-22Z FOR
CMH/DAY/LCK WHEN WINDS SHIFT NORTHWEST AND NORTH AND THE THREAT
FOR A SHOWER WILL BE HEIGHTENED. ATTM...IF SHOWERS ARE PRESENT
THIS TIME TOMORROW EVENING IT IS A TOSS UP AS TO RAIN OR SNOW.
EITHER WILL BE POSSIBLE BUT BARELY TIC THE VSBYS INTO THE MVFR
CATEGORY. CIGS WITH THE POTENTIAL RAIN AND IN THE POST-FRONTAL
ATMOSPHERE WILL DEFINITELY DROP TO MVFR AND POSSIBLY TICKLE 1KFT IN
SPOTS.

OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE SATURDAY NIGHT AND AGAIN
TUESDAY NIGHT INTO WEDNESDAY.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...HICKMAN
NEAR TERM...FRANKS
SHORT TERM...HICKMAN
LONG TERM...HATZOS
AVIATION...FRANKS