Special Marine Warning 16, NWS Cleveland, OH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CLEVELAND OH
611 PM EDT MON MAY 28 2012

.SYNOPSIS...
A COLD FRONT OVER THE MISSISSIPPI VALLEY WILL MOVE EAST ACROSS THE
REGION TUESDAY AND ALLOW MUCH COOLER HIGH PRESSURE TO BUILD INTO
THE REGION FOR WEDNESDAY AND THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPDATED THE EASTERN AREAS FOR SCATTERED SHOWERS AND THUNDERSTORMS
THIS EVENING...THEN WAITING FOR MORE TO DEVELOP OVERNIGHT FROM THE
APPROACHING COLD FRONT. NO CHANGES TO TEMPERATURES ATTM.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
THE COLD FRONT WILL CROSS THE REGION TUESDAY WITH SCATTERED
CONVECTION ALONG AND AHEAD OF THE FEATURE. THE SREF CALIBRATED
SEVERE PARAMETER IS AROUND 5 TUESDAY AFTERNOON WHICH IS NOT OVERLY
HIGH SO THE THREAT OF SEVERE WEATHER IS FAIRLY LOW ESPECIALLY IN
THE WEST WHERE THE FRONTAL BOUNDARY WILL PASS SOONER. MORE STABLE
AIR WILL MOVE INTO THE REGION BY WEDNESDAY AS HIGH PRESSURE BUILDS
INTO THE REGION. THE AIR IS SO COOL SOME LAKE INDUCED INSTABILITY
CLOUDS MAY FORM ON WEDNESDAY AND LINGER OVER NIGHT. ON THURSDAY
FAIR WEATHER SHOULD CONTINUE WITH HIGH PRESSURE BUILDING BY TO THE
NORTH. HAVE USED THE MET GUIDANCE WITH MINOR CHANGES.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
EXTENDED PERIODS APPEAR TO BE RATHER WET AS UPPER LEVEL PATTERN
TRANSITIONS INTO AN AMPLIFIED SITUATION. LATEST GUIDANCE INDICATES
SOME STRONG AMPLIFICATION IN THE 500 MB RIDGE ON THE WEST COAST
WHICH TRANSLATES INTO A DIGGING TROUGH IN THE CENTRAL UNITED STATES.
THE GOOD NEWS IS THAT THE DIGGING TROUGH QUICKLY FILLS AND THE UPPER
LEVEL FLOW BECOMES MORE ZONAL ACROSS THE UNITED STATES BY THE END OF
THE FORECAST PERIOD.

SURFACE LOW IS EXPECTED TO MOVE A BIT FURTHER WEST INTO ILLINOIS AND
INDIANA ON FRIDAY. THIS PLACES THE FORECAST AREA MORE INTO THE WARM
SECTOR AFTER WARM FRONT LIFTS NORTH. THERE MAY BE A SLIGHT DELAY IN
THE ONSET OF THE PRECIPITATION FRIDAY. EARLIER RUNS INDICATED THREAT
FOR SHOWERS WOULD BEGIN EARLY FRIDAY MORNING. NOW IT APPEARS THAT
THE SHOWERS WILL HOLD OFF UNTIL EARLY AFTERNOON. A COLD FRONT WILL
SWEEP EAST ON FRIDAY AND THE BIG QUESTION IS HOW MUCH CONVECTION
DEVELOPS ACROSS THE DEEP SOUTH TO CUT OFF THE MOISTURE FLOW NORTH
FROM THE GULF OF MEXICO.

SINCE LOW IS TAKING A TRACK FURTHER WEST...WILL EXPAND THE LIKELY
CATEGORY RAIN FOR THE WESTERN PORTIONS OF THE FORECAST AREA ON
FRIDAY.

LOW PULLS OFF TO THE NORTHEAST FRIDAY NIGHT INTO SATURDAY AND A
TROUGH WILL SWING EAST ACROSS THE AREA ON SATURDAY WITH WRAP AROUND
MOISTURE. SHOWERS WILL LINGER OVER THE EASTERN HALF OF THE AREA
SATURDAY NIGHT AND EVEN ON SUNDAY.

SURFACE AND WEAK UPPER LEVEL RIDGE BUILD EAST ACROSS THE AREA BUT
FAIR WEATHER WILL BE SHORT LIVED. WARM FRONT LIFTS INTO THE REGION
WITH A FAST MOVING UPPER LEVEL SHORTWAVE AND ASSOCIATED MOISTURE.
THIS SHOULD BRING ANOTHER SHOT FOR SHOWERS AND THUNDERSTORMS SUNDAY
NIGHT INTO MONDAY. THE THREAT WILL CONTINUE ALL THE WAY INTO TUESDAY
AS WEAK COLD FRONT APPROACHES.

TEMPERATURES IN THE LAST FEW MODEL RUNS HAVE BEGUN TO MODERATE FOR
THE EXTENDED PERIODS DUE THE FURTHER WEST TRACK OF THE LOW PRESSURE
SYSTEM ON FRIDAY. COOL TEMPERATURES IN THE COLD AIR ADVECTION
EXPECTED SATURDAY AND SATURDAY NIGHT. RIDGE WILL BRING A RETURN BACK
TO THE 70S FOR HIGHS ON SUNDAY FOLLOWED BY WARM AIR ADVECTION SUNDAY
NIGHT INTO MONDAY.

&&

.AVIATION /22Z MONDAY THROUGH SATURDAY/...
CUMULUS CONTINUES TO DEVELOP BETWEEN 3500 AND 5000 FEET ABOVE THE
SURFACE NOW THAT THE CAP HAS BROKEN. WINDS HAVE BEEN GUSTING TO 15
KNOTS IN SOME PLACES AND EXPECT THE WIND TO REMAIN AROUND 12 KNOTS
OR SO THROUGH THE REST OF THE DAY.

COLD FRONT IS EXPECTED TO MOVE EAST ACROSS THE AREA BY TOMORROW
MORNING. EXPECTING THE POSSIBILITY FOR CONVECTION TO DEVELOP AHEAD
OF THE COLD FRONT. AS FRONT MOVES FROM WEST TO EAST BETWEEN ABOUT
12Z AND 17Z...CEILINGS WILL GRADUALLY IMPROVE THROUGH THE MORNING
HOURS.

.OUTLOOK...NON VFR POSSIBLE IN WIDESPREAD SHRA FRIDAY.

&&

.MARINE...
A LAKE BREEZE ESPECIALLY OVER THE EASTERN LAKESHORE AREAS WILL
DIMINISH THIS EVENING...ALLOWING FOR MORE PREDOMINATE SOUTHERLY FLOW
OVER THE LAKE THROUGH TONIGHT. A COLD FRONT WILL MOVE EAST ACROSS
THE LAKE THROUGH TUESDAY SHIFTING WINDS TO THE WEST DURING THE
AFTERNOON. WINDS LOOK TO SHIFT BACK SW TUESDAY EVENING/EARLY TUESDAY
NIGHT AHEAD OF A SECONDARY COLD FRONT THAT WILL MOVE ACROSS THE
LAKE. WINDS WILL SHIFT TO THE WNW/NW BY WEDNESDAY MORNING.

HIGH PRESSURE OVER THE UPPER MIDWEST WILL BUILD EAST TOWARD THE
GREAT LAKES. WINDS WILL INCREASE AS THE HIGH MOVES TOWARD THE AREA
WEDNESDAY AFTERNOON AND NIGHT. THIS WILL BE THE NEXT POSSIBLE SMALL
CRAFT ADVISORY PERIOD DURING THE FORECAST. HIGH PRESSURE SETTLES
OVER THE LAKE THURSDAY ALLOWING FOR QUIETER CONDITIONS. A LOW
PRESSURE SYSTEM MAY BRING UNSETTLING CONDITIONS OVER THE LAKE FOR
THE END OF THE WEEK.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.

&&

SYNOPSIS...REL
NEAR TERM...KIELTYKA
SHORT TERM...REL
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...ABE