839
FXUS61 KILN 200855
AFDILN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
355 AM EST THU FEB 20 2020
SYNOPSIS
HIGH PRESSURE WILL BUILD INTO THE AREA TODAY THROUGH FRIDAY AND
THEN PERSIST THROUGH THE WEEKEND. THE NEXT PRECIPITATION WILL
NOT SPREAD INTO THE REGION UNTIL MONDAY AHEAD OF THE A STORM
SYSTEM.
NEAR TERM /UNTIL 6 AM THIS MORNING/
EXTENSIVE HIGH AND MID CLOUDS ASSOCIATED WITH A JET STREAK WILL
CONTINUE TO MOVE ACROSS THE AREA THIS MORNING. THESE CLOUDS WILL
CLEAR IN THE AFTERNOON AS THE JET STREAK HEADS EAST. BUT THE
INCREASE IN INSOLATION MAY RESULT IN SOME STRATOCUMULUS
DEVELOPING. HIGHS WILL BE OVER 10 DEGREES BELOW NORMAL. NORTH
WINDS WILL INCREASE A BIT THIS AFTERNOON AND WIND CHILLS WILL
GET NO HIGH THAN THE LOWER 20S.
SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/
POSITIVELY TILTED MID LEVEL TROUGH WILL PASS ACROSS THE AREA
TONIGHT FOLLOWED BY NORTHWEST FLOW. MEANWHILE HIGH PRESSURE AT
THE SURFACE WILL BUILD INTO THE REGION. AIRMASS WILL BE COLD
AND VERY DRY WITH LITTLE IF ANY CLOUD COVER. TEMPERATURES WILL
GENERALLY DROP INTO THE MID TEENS TONIGHT. READINGS WILL REBOUND
A BIT ON FRIDAY BUT STILL BE WELL BELOW NORMAL.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
ON FRIDAY NIGHT, THE CENTER OF A LARGE AREA OF SURFACE HIGH PRESSURE
WILL BE LOCATED OVER WESTERN TENNESSEE. THIS HIGH WILL COVER A LARGE
EXPANSE OF REAL ESTATE, FROM THE LOWER MISSISSIPPI VALLEY THROUGH
THE GREAT LAKES, AND AS FAR EAST AS THE VIRGINIA COAST. THE HIGH
WILL ALSO BRING AN ESPECIALLY DRY AIR MASS, WITH PRECIPITABLE WATER
VALUES OVER THE ILN FORECAST AREA OF AROUND A TENTH OF AN INCH. AS
THE HIGH GRADUALLY DRIFTS EAST OVER THE WEEKEND, WINDS WILL SHIFT
AROUND TO THE SOUTH, BRINGING A WARMING TREND THROUGH THE FIRST FEW
DAYS OF THE EXTENDED FORECAST PERIOD. THIS WILL BEGIN AFTER ANOTHER
COOL NIGHT ON FRIDAY NIGHT INTO SATURDAY MORNING, WITH MIN
TEMPERATURES AROUND 20 DEGREES. AFTER THAT, WARM ADVECTION IN SUCH A
DRY AIR MASS WILL SEE TEMPERATURES RISE AS MUCH AS 25 TO POSSIBLY 30
DEGREES, WITH DAYTIME MAX TEMPS ON SATURDAY IN THE MIDDLE TO UPPER
40S.
AFTER ANOTHER DAY OF WARMING ON SUNDAY, ATTENTION WILL TURN TO
UPSTREAM CYCLOGENESIS, AS A TROUGH MOVING OUT OF THE FOUR CORNERS
AREA IS EXPECTED TO DEVELOP A SURFACE LOW OVER THE TX/OK PANHANDLE
AREA BY SUNDAY EVENING. AS THIS TROUGH MOVES EAST ON MONDAY, IT IS
GENERALLY EXPECTED TO WEAKEN, MOVING MORE QUICKLY AS IT PASSES
THROUGH THE OHIO VALLEY ON MONDAY AND MONDAY NIGHT. OVERALL MODEL
AGREEMENT (AND THUS FORECAST CONFIDENCE) IS FAIR WITH REGARD TO THE
SYSTEM OVERALL, BUT SPECIFICS ON THE SURFACE LOW TRACK AND SPEED OF
THE TROUGH ARE OF SLIGHTLY LOWER CONFIDENCE. IT IS IN THIS PERIOD OF
THE FORECAST (SUNDAY NIGHT INTO MONDAY EVENING) WHERE GEFS SPREAD
INCREASES SIGNIFICANTLY, SUGGESTING THAT THE DETAILS REMAIN FUZZY
WITH REGARDS TO HOW THIS SYSTEM IS GOING TO BEHAVE. WHAT DOES LOOK
LIKELY IS THAT IT WILL BE PRIMARILY AN ISSUE OF RAIN, AS
TEMPERATURES WILL BE TOO WARM FOR MUCH (IF ANY) SNOW MIXING IN AT
THE BEGINNING, AND ONLY COOLING DOWN ENOUGH FOR SNOW AT THE END OF
THE EVENT AFTER THE STRONGER FORCING HAS DEPARTED. NON-DIURNAL
TEMPERATURES ALSO APPEAR LIKELY, PARTICULARLY MONDAY NIGHT -- WITH
WARM ADVECTION CONTINUING UNTIL THE SURFACE LOW HAS PASSED THROUGH
THE AREA. OVERALL, THIS DOES NOT APPEAR LIKELY TO BE A PARTICULARLY
IMPACTFUL SYSTEM FOR THE ILN CWA, BUT AS MENTIONED, THE SPECIFICS
ARE STILL SOMEWHAT UNCLEAR AT THIS DISTANCE IN THE FORECAST.
BEYOND MONDAY NIGHT, IT APPEARS THAT THE NEXT CHANCE FOR
PRECIPITATION WILL COME ON TUESDAY NIGHT INTO WEDNESDAY, AS ANOTHER
TROUGH ROTATES SOUTHEAST THROUGH THE UPPER MIDWEST AND GREAT LAKES
REGIONS. AT THIS POINT, TEMPERATURES WILL BE COOLER, WITH COLD
ADVECTION EXPECTED BEHIND THE MONDAY SYSTEM. THUS, THERE MAY BE A
CHANCE FOR SOME SNOW TO MIX IN AT SOME POINT BY THE MIDDLE OF NEXT
WEEK.
AVIATION /09Z THURSDAY THROUGH MONDAY/
VFR WILL PREVAIL THROUGH THE PERIOD. HIGH AND MID CLOUDS WILL
STREAM ACROSS THE REGION AND THEN CLEAR FROM NORTHWEST TO
SOUTHEAST AFTER 18Z. BUT SOME SCATTERED STRATOCUMULUS MAY
DEVELOP ONCE THESE HIGHER CLOUDS MOVE OUT. SKIES WILL CLEAR BY
00Z. NORTHERLY WINDS WILL INCREASE TO 10 TO 15 KT DURING THE DAY
AND THEN SLOWLY DIMINISH LATE IN THE PERIOD.
OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE ON MONDAY.
ILN WATCHES/WARNINGS/ADVISORIES
OH...NONE.
KY...NONE.
IN...NONE.
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...HATZOS
AVIATION...
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page