900
FXUS63 KIWX 212354
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
754 PM EDT TUE MAY 21 2019
SYNOPSIS
ISSUED AT 422 AM EDT TUE MAY 21 2019
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS EXPECTED LATE
TONIGHT INTO WEDNESDAY. IT APPEARS THIS RAINY PATTERN WILL
PERSIST THROUGH MEMORIAL DAY WITH PERIODIC CHANCES FOR SHOWERS AND
STORMS. HEAVY RAIN IS POSSIBLE AT TIMES. MUCH WARMER WEATHER WITH
TEMPERATURES IN THE 70S TO MID 80S FROM THURSDAY THROUGH EARLY
NEXT WEEK.
SHORT TERM
(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 321 PM EDT TUE MAY 21 2019
RESIDUAL LINE OF EARLY MORNING SHOWERS HAS FINALLY MOVED
NORTHWARDS THIS AFTERNOON. PERSISTENT CLOUD COVERAGE AND COOL
POST-FRONTAL AIRMASS IN PLACE HAS CAUSED TEMPERATURES TO STRUGGLE
TO REACH THE MID 50S. A SECONDARY AREA OF SCATTERED SHOWERS IS
DEVELOPING ALONG AND SOUTH OF HWY30 AS AN EMBEDDED SHORTWAVE
PROGRESSES THROUGH THE LOWER OHIO RIVER VALLEY. A FEW LIGHTNING
STRIKES HAVE BEEN OBSERVED ACROSS SOUTHERN INDIANA WHICH IS MUCH
CLOSER TO THE SHORTWAVE AND DID WHERE A FEW BREAKS IN THE CLOUDS
WHERE EARLIER ON IN THE DAY. CHANCES FOR THUNDER IN THE CWA ARE
FAIRLY LOW GIVEN OUR PERSISTENT CLOUD COVER, AND THE TRACK OF THE
SHORTWAVE WILL STAY WELL SOUTH. THESE SHOWERS ARE ANTICIPATED TO
DIMINISH IN AREAL EXTENT IN THE 5-7PM EDT TIMEFRAME. THIS WILL
START A RELATIVE LULL IN SHOWER ACTIVITY UP TO MIDNIGHT.
AFTER MIDNIGHT, UPPER LOW MOVING ACROSS THE CENTRAL PLAINS WILL
SEND A FRONT, WITH ONGOING CONVECTION ALONG THE FRONT, ACROSS IL
AND INTO WESTERN IN. AS STORMS SLOWLY MOVE ACROSS THE AREA THROUGH
THE OVERNIGHT HOURS AND INTO WEDNESDAY, THEY WILL GRADUALLY LOSE
UPPER LEVEL SUPPORT AS THE RIGHT EXIT REGION OF THE JET MOVES
OVER THE CWA. FRONT MOVES OVER THE EASTERN ZONES BY TOMORROW
AFTERNOON. MODELS SHOW SOME INCREASE IN INSTABILITY ACROSS NW OHIO
AND EASTERN IN DURING THE AFTERNOON HOURS WHICH COULD ALLOW FOR
STORMS TO BECOME MORE EFFICIENT RAIN PRODUCERS. GIVEN THAT SOILS
REMAIN SATURATED, ANY ADDITIONAL RAINFALL WILL LIKELY PROLONG OR
AGGRAVATE ONGOING FLOODING.
LONG TERM
(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 321 PM EDT TUE MAY 21 2019
WEDNESDAY NIGHT INTO THURSDAY, THE REMNANT CENTRAL PLAINS LOW WHICH
WILL BRING RAIN TOMORROW WILL START TO EJECT ACROSS THE UPPER
MIDWEST. THIS WILL SEND ANOTHER FRONT INTO THE AREA AND PROVIDE A
FOCUS FOR YET ANOTHER ROUND OF STORMS. WITH PWATS REMAINING IN THE
1.25-1.5" RANGE, THIS ROUND OF STORMS COULD BRING PERIODS OF
HEAVY RAIN. AS MENTIONED ABOVE, THIS WILL PROLONG OR AGGRAVATE
ONGOING FLOODING. FRONT BECOMES STALLED OVER THE AREA THURSDAY
NIGHT INTO THE WEEKEND AS THE UPPER FLOW BECOMES ZONAL IN RESPONSE
TO A BUILDING SUB-TROPICAL HIGH OVER THE SE US. THIS WILL BRING
PERIOD OF SHOWERS AND THUNDERSTORMS INTO THE MEMORIAL DAY WEEKEND
WITH TEMPERATURES IN THE 70S AND 80S. UPPER RIDGE BREAKS DOWN
EARLY NEXT WEEK AND A VIGOROUS LOW MOVES ACROSS THE NORTHERN
PLAINS.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 739 PM EDT TUE MAY 21 2019
LARGE LINE OF STRONG TO SEVERE STORMS ENTERING WESTERN ILLINOIS
WILL CONTINUE TO TRACK NORTHEAST, WITH THE WESTERN EDGE POSSIBLY
REACHING KSBN BY 7Z IN A MUCH WEAKER FASHION. STILL SOME CHANCE
FOR THUNDER ALONG THE LEADING EDGE BUT NOT AS CONFIDENT SO HAVE
OPTED FOR TEMPO THUNDER AT KSBN OVERNIGHT. KEPT THUNDER OUT OF
KFWA AS INSTABILITY WILL BE SERIOUSLY LACKING THERE AND
QUESTIONABLE EXACTLY HOW FAR EAST THE PRECIP MAKES IT. COULD SEE
SOME MVFR CIGS/VSBY IN HEAVIER SHOWERS OR STORMS, BUT SHOULD BE
SHORT DURATION.
RAIN SHOULD QUICKLY EXIT DURING THE LATER MORNING WITH CLEARING
SKIES THE REMAINDER OF THE PERIOD.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT WEDNESDAY FOR LMZ043-046.
SYNOPSIS...SKIPPER/CM
SHORT TERM...CM
LONG TERM...CM
AVIATION...FISHER
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