-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 221309
AFDILN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
909 AM EDT WED MAY 22 2013

.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES TODAY...WITH A
COLD FRONT MOVING INTO THE OHIO VALLEY TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AHEAD OF THIS FRONT. A SECONDARY
TROUGH WILL BRING A CHANCE OF RAIN AGAIN ON THURSDAY. MUCH COLDER
AIR WILL MOVE INTO THE REGION ON FRIDAY...AS HIGH PRESSURE BUILDS
INTO THE OHIO VALLEY THROUGH SATURDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
SATELLITE IMAGERY SHOWS CONSIDERABLE CLOUDS ACROSS THE WESTERN
PART OF THE FORECAST AREA WITH LITTLE CLOUD COVER IN THE EAST. A
FEW SHOWERS HAVE BEEN LIFTING UP THROUGH WESTERN SECTIONS. IT DOES
NOT APPEAR THAT THERE WILL BE MUCH MORE THAN JUST WIDELY SCATTERED
SHOWERS THROUGH THE REST OF THE MORNING.

DESTABILIZATION WILL OCCUR THROUGH THE DAY AND GUIDANCE SUGGESTS
THAT THE SOUTHEASTERN COUNTIES WILL BECOME THE MOST UNSTABLE
DURING THE AFTERNOON WITH A GOOD DEAL OF HEATING AND SLIGHTLY
HIGHER DEW POINTS. FORECAST SHEAR LOOKS A LITTLE BETTER THAN
YESTERDAY ALTHOUGH STILL ON THE MARGINAL SIDE WHERE THE MORE
UNSTABLE AIR IS EXPECTED. STILL SOME QUESTION ON THE AMOUNT OF
INSTABILITY THAT WILL BE REALIZED IN WESTERN SECTIONS.

GUIDANCE...EVEN IN THE CONVECTION ALLOWING MODELS...IS NOT IN
AGREEMENT WITH HOW SCENARIO WILL EVOLVE LATER TODAY. STRONGER
SIGNAL SEEMS TO INDICATE THAT SHOWERS AND THUNDERSTORMS WILL
DEVELOP DURING THE AFTERNOON IN THE SOUTHERN COUNTIES AND LIFT
NORTHEAST LATE IN THE AFTERNOON AND INTO THE EVENING. HAVE
MAINTAINED LIKELY POPS ALTHOUGH THERE IS THE POTENTIAL FOR
COVERAGE TO BE LESS THAN THAT. AT THIS POINT APPEARS THAT THE
GREATER POTENTIAL FOR STRONG TO SEVERE STORMS WILL BE IN THE
SOUTHEAST WHERE FORECAST INSTABILITY IS HIGHER. BUT THIS WILL HAVE
TO BE MONITORED AS THE DAY UNFOLDS. DAMAGING STRAIGHT LINE WINDS
STILL SEEM TO BE THE GREATEST SEVERE WEATHER THREAT.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE INITIAL COLD FRONT WILL BE CROSSING THE ILN CWA DURING THE
EVENING HOURS...PRODUCING A RELATIVELY SMALL CHANGE IN THE
TEMPERATURE AND WIND FIELDS. BEHIND THE FRONT...PRECIPITATION WILL
BECOME LESS LIKELY...ESPECIALLY IN THE SOUTH AND SOUTHWEST
PORTIONS OF THE CWA.

A SECONDARY TROUGH (BOTH ALOFT AND AT THE SURFACE) WILL BE
ROTATING SOUTHEAST THROUGH THE CWA ON THURSDAY. THIS WILL BRING A
RENEWED CHANCE OF PRECIPITATION...ESPECIALLY IN THE NORTHERN AND
EASTERN PARTS OF THE CWA. INSTABILITY WILL BE VERY WEAK...BUT JUST
ENOUGH FOR SOME RISK OF THUNDER. THE AIR MASS ALOFT WILL BE
INCREASINGLY COLD...HELPING TO LEAD TO THE POSSIBILITY OF
CONVECTIVE SHOWERS.

ALONG WITH THIS ACTIVITY WILL BE A SECONDARY COLD FRONT...MUCH
BETTER DEFINED THAN THE FIRST. A NNW WIND SHIFT WILL ALLOW FOR
COLD ADVECTION TO BEGIN ON THURSDAY (AND ESPECIALLY THURSDAY
NIGHT). AS A RESULT...THE MAX TEMP GRADIENT FOR THURSDAY IS
SOMEWHAT SHARP (ABOUT 10 DEGREES FROM SW TO NE) AND THURSDAY
NIGHT MIN TEMPS MAY GET INTO THE 30S IN THE NORTHERN PORTIONS OF
THE CWA.

WITH DRY HIGH PRESSURE IN PLACE FOR FRIDAY...RELATIVELY TRANQUIL
CONDITIONS ARE EXPECTED.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
DRY WEATHER SHOULD CONTINUE ON SATURDAY FOR MOST OF THE AREA
EXCEPT FOR FAR SOUTHEAST COUNTIES WHERE A DEVELOPING FRONTAL
BOUNDARY MAY CAUSE A FEW SHOWERS.

FOR SUNDAY THROUGH TUESDAY...THAT FRONTAL BOUNDARY IS FORECAST TO
LINGER ACROSS KENTUCKY. THIS PATTERN WILL PROVIDE A CHANCE OF
SHOWERS EACH DAY TO THE SOUTHERN PART OF THE FORECAST AREA...WITH
NORTHERN LOCATIONS ENJOYING A PERIOD OF DRY WEATHER.

SLIGHTLY BELOW NORMAL HIGHS AVERAGING IN THE LOWER 70S ON THURSDAY
WILL BE FOLLOWED BY BELOW NORMAL 60S ON FRIDAY UNDER CLOUDS AND
SHOWERS. TEMPERATURES WILL THEN GRADUALLY REBOUND FROM SATURDAY
ONWARD...WITH HIGHS REACHING THE MID AND UPPER 70S BY TUESDAY.

&&

.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
REGION WILL REMAIN IN A MOIST SOUTH TO SOUTHWEST FLOW AT THE
SURFACE AND ALOFT AS THE CENTER OF AN UPPER LEVEL LOW PIVOTS
SOUTHEAST TOWARD THE WESTERN GREAT LAKES. AS THE LOW MOVES
SOUTHEAST...A SURFACE COLD FRONT WILL PUSH EAST THROUGH OUR AREA
TONIGHT.

LATEST ANALYSIS AND MODELS INDICATE THAT OUR AREA IS STILL IN AN
INSTABILITY MINIMUM THIS MORNING. FOR THIS AFTERNOON INTO THIS
EVENING...THE PROSPECTS OF SHOWERS AND THUNDERSTORMS WILL INCREASE
AS DAYTIME HEATING INTERACTS WITH LARGE SCALE SYNOPTIC LIFT. BEST
CHANCE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE FROM MID
AFTERNOON INTO THE EVENING HOURS. HAVE PLACED THIS IN THE TAFS
WITH A PREDOMINANT MVFR -SHRA AND A VCTS/CB. AS STORMS BECOME MORE
APPARENT AND CAN BE TRACKED ON RADAR...TAFS WILL BE FINED TUNED
ACCORDINGLY. WITH A MOIST AIRMASS...SOME LOCAL MVFR CIGS AND IFR
VSBYS WILL BE POSSIBLE IN THUNDERSTORMS. DAYTIME HEATING/MIXING
WILL PRODUCE SOUTH/SOUTHWEST WINDS OF 12-16 KNOTS WITH GUSTS UP TO
30 KNOTS.

FOR TONIGHT...THE COLD FRONT IS FORECAST TO PUSH EAST ACROSS THE
REGION. LARGE SCALE LIFT DECREASES AS DOES THE INSTABILITY.
HOWEVER...MODELS INDICATE THAT THERE COULD BE A BAND OF SHOWERS
AND A FEW EMBEDDED THUNDERSTORMS ALONG AND AHEAD OF THE FRONT.
HAVE INDICATED THIS WITH A VCSH AS THUNDERSTORMS CHANCES WILL WANE
BETWEEN 01Z AND 06Z. AFTER FRONTAL PASSAGE...THERE SHOULD BE A
REPRIEVE IN PCPN BUT LOW LEVEL MOISTURE WILL REMAIN. IT IS UNCLEAR
AT THIS TIME IF MVFR CEILINGS WILL DEVELOP BEHIND THE FRONT SO
HAVE LEFT THEM AT VFR FOR NOW.

OUTLOOK...MVFR CONDITIONS POSSIBLE WITH SHOWERS AND EMBEDDED
THUNDERSTORMS THURSDAY INTO THURSDAY EVENING.
-- End Changed Discussion --

&&

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

&&

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