243
FXUS63 KDVN 010601
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
101 AM CDT TUE APR 1 2025
KEY MESSAGES
- A STRONG STORM SYSTEM WILL IMPACT THE MIDWEST TUESDAY NIGHT
INTO WEDNESDAY. SEVERE STORMS ARE POSSIBLE, ESPECIALLY EAST OF
THE MISSISSIPPI ON WEDNESDAY WITH ALL HAZARDS POSSIBLE.
- OUTSIDE OF WEDNESDAY, TEMPERATURES LOOK TO BE NEAR OR SLIGHTLY
BELOW NORMAL FOR EARLY APRIL.
- A SOMEWHAT ACTIVE WEATHER PATTERN CONTINUES LATE THIS WEEK
WITH TWO ADDITIONAL BUT WEAKER SYSTEMS MOVING THROUGH THE
MIDWEST.
SHORT TERM /THROUGH WEDNESDAY/
ISSUED AT 251 PM CDT MON MAR 31 2025
QUIET AND CHILLY CONDITIONS WILL BE SEEN LATE THIS AFTERNOON AND
TONIGHT AS CANADIAN HIGH PRESSURE MOVES THROUGH THE MIDWEST.
ATTENTION THEN TURNS TO THE NEXT STORM SYSTEM.
TUESDAY MORNING WILL REMAIN DRY ACROSS THE AREA AS HIGH LEVEL
MOISTURE STREAMS INTO THE AREA. AS LOWER LEVEL MOISTURE BEGINS TO
ARRIVE TUESDAY AFTERNOON, ISOLATED TO SCATTERED SHOWERS ARE EXPECTED
TO DEVELOP ACROSS EASTERN IOWA BY MID TO LATE AFTERNOON.
TUESDAY NIGHT INTO WEDNESDAY WILL BE QUITE INTERESTING.
AS THE LLJ INCREASES TUESDAY EVENING, AREAL COVERAGE OF THE RAIN
SHOWERS WILL INCREASE AS DEEPER LOW LEVEL MOISTURE ALOFT MOVES INTO
THE AREA.
THUNDERSTORMS WILL INITIATE BY LATE EVENING AND CONTINUE OVERNIGHT AS
AREAL COVERAGE OF THE RAIN CONTINUES TO INCREASE. WITH THE WARM
FRONT STILL IN MISSOURI, THE STORMS WILL BE ELEVATED AND FAST
MOVING. LAPSE RATES ARE FAVORABLE FOR HAIL GENERATION, AND, IF
SEVERE STORMS DEVELOP, HAIL WOULD BE THE PRIMARY RISK. CSU SEVERE
PROBABILITIES PEG A 5-15% PROBABILITY OF HAIL FOR AREAS SOUTH OF I-
80. HOWEVER, THERE IS ALSO A LOW RISK (5-10%) FOR WIND. THIS
SUGGESTS THAT WHILE STORMS WILL BE ELEVATED, A ROGUE SEVERE
DOWNBURST CANNOT BE RULED OUT.
THE SEVERE RISK WEDNESDAY IS DEPENDENT UPON HOW STORMS EVOLVE
TUESDAY NIGHT. IF AREAL COVERAGE OF STORMS IS LOW OR STORMS CLEAR
OUT EARLY, THEN THE SEVERE POTENTIAL WOULD INCREASE ON WEDNESDAY.
BASED ON THE 12Z MODEL SUITE, THE WARM FRONT MOVES NORTH INTO THE
AREA VERY LATE TUESDAY NIGHT AND WEDNESDAY MORNING. STORMS ALONG AND
NEAR THE WARM FRONT WOULD HAVE THE POTENTIAL TO BE SURFACE BASED AND
THUS ADD THE SEVERE WIND RISK TO THE HAIL. IN A CLOSER LOOK AT THE
MODELS, ONE CAN INFER A WEAK LOW AND TRIPLE POINT ALONG THE
MISSISSIPPI RIVER AT SUNRISE WEDNESDAY. THIS FEATURE MOVES EAST
NORTHEAST OR NORTHEAST THROUGH MID-DAY WEDNESDAY AND COULD BE AN
ENHANCER TO KEEP STORMS STRONG TO POTENTIALLY SEVERE WEDNESDAY
MORNING OVER THE AREA.
MOST MODELS HAVE THE COLD FRONT OR A PRE-FRONTAL TROF ALONG THE
MISSISSIPPI AT MID-DAY WEDNESDAY. THIS FEATURE WILL LIKELY BE THE
INITIATOR FOR THE DIURNAL SEVERE STORMS AND THUS ITS POSITION AND
TIMING WILL BE CRITICAL IN DETERMINING THE OVERALL SEVERE RISK.
FROM THE SYNOPTIC LEVEL, THE SIGNALS FOR SEVERE STORMS ARE MUCH MORE
FAVORABLE OVER THE OHIO VALLEY SOUTHWEST INTO ARKANSAS. INDEED, THE
CSU SEVERE PROBABILITIES ARE TAGGING THE SAME AREAS WITH A SUBTLE
EASTWARD SHIFT FROM THE 00Z TO 12Z PROBABILITIES ACROSS EASTERN IOWA
AND NORTHERN ILLINOIS.
THUS IF SEVERE STORMS OCCUR ACROSS EASTERN IOWA INTO ILLINOIS, HAIL
AND WIND ARE THE PRIMARY RISKS ON WEDNESDAY. HOWEVER, NEAR ANY
BOUNDARY, ISOLATED TORNADOES CANNOT BE RULED OUT.
IN LOOKING OVER THIS UPCOMING STORM SYSTEM, THERE ARE SIMILARITIES
AND DIFFERENCES BETWEEN THIS SYSTEM AND THE ONE LAST WEEKEND.
POSITION AND TRACK OF THE LOWS ARE SIMILAR. THE DIFFERENCES ARE THE
MUCH BETTER AND STRONGER SIGNAL FOR A SIGNIFICANT SEVERE OUTBREAK.
HOWEVER, THE SEVERE RISK AREA FOR THIS EVENT IS ALSO SIMILAR TO THE
ONE OVER THE WEEKEND. THUS THE POSSIBILITY DOES EXIST, ROUGHLY A 8
TO 18 PERCENT CHANCE, THAT SEVERE STORMS COULD BISECT THE AREA. THAT
IS, REMAIN WELL WEST AND SOUTHWEST OF THE AREA TUESDAY NIGHT AND
THEN WELL EAST AND SOUTHEAST OF THE AREA ON WEDNESDAY. TIME WILL
TELL IS THIS SCENARIO PLAYS OUT.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
ISSUED AT 251 PM CDT MON MAR 31 2025
WEDNESDAY NIGHT
ASSESSMENT...HIGH (>80%) CONFIDENCE OF DRY CONDITIONS
THE COLD FRONT WILL EXIT THE AREA WEDNESDAY EVENING LEAVING DRY BUT
BREEZY CONDITIONS ACROSS THE AREA. ATTENTION THEN TURNS TO THE
WEAKER SYSTEMS FOR LATE IN THE WEEK.
THURSDAY THROUGH SATURDAY NIGHT
ASSESSMENT...MEDIUM TO HIGH (60-80%) CONFIDENCE ON TWO SYSTEMS.
MEDIUM (35-55%) CONFIDENCE REGARDING RAIN CHANCES
A WEAK SYSTEM MOVING THROUGH THE FLOW ALOFT LOOKS TO SIDE-SWIPE THE
SOUTH HALF OF THE AREA THURSDAY/THURSDAY NIGHT. MOISTURE IS VERY
LIMITED WITH THIS SYSTEM AND THE BETTER FORCING IS ACROSS THE
SOUTHERN HALVES OF MISSOURI AND ILLINOIS. THE MODEL CONSENSUS HAS A
20-30 PERCENT CHANCE OF RAIN. GIVEN THE LIMITED MOISTURE, THERE IS A
20 PERCENT CHANCE THAT THURSDAY/THURSDAY NIGHT REMAINS DRY FOR THE
ENTIRE AREA.
A CLIPPER SYSTEM WILL MOVE THROUGH THE UPPER MIDWEST FRIDAY INTO
FRIDAY NIGHT AND PUSH A STRONG COLD FRONT THROUGH THE AREA. THE
MODEL CONSENSUS IS TARGETING FRIDAY NIGHT FOR THE BEST CHANCES FOR
RAIN (30-60%). COLD ADVECTION ON SATURDAY WILL KEEP THE RISK OF
ISOLATED TO SCATTERED (20-40%) RAIN SHOWERS GOING THROUGH THE DAY
WITH SHOWERS SLOWLY DISSIPATING SATURDAY NIGHT.
SUNDAY THROUGH MONDAY
ASSESSMENT...HIGH (>80%) CONFIDENCE OF COOLER THAN NORMAL
TEMPERATURES
DRY BUT COOL CONDITIONS WILL BE SEEN ACROSS THE AREA SUNDAY THROUGH
MONDAY AS CANADIAN HIGH PRESSURE BUILDS INTO THE MIDWEST.
TEMPERATURES WILL AVERAGE BELOW NORMAL.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1243 AM CDT TUE APR 1 2025
HIGH PRESSURE IS IN PLACE ACROSS THE AREA EARLY THIS MORNING AND
IS FORECAST TO SHIFT EASTWARD DURING THE DAY. THIS WILL TURN
SURFACE WINDS TO THE SOUTHEAST AFTER 12 UTC AND INCREASE TO 10
TO 20 KNOTS THROUGH THE MORNIGN HOURS WITH GUSTS UP TO 30 KNOTS
THROUGH THE REMAINDER OF THE PERIOD. TAFS THROUGH THE PERIOD
WILL BE VFR.
A STORM SYSTEM APPROACHINGTHE AREA WILL BRING LOW CHANCE FOR
SHOWERS AFTER 18 UTC AND THE CHANCE FOR THUNDERSTORMS AFTER 00
UTC. TIMING AT THIS TIME IS LOW CONFIDENCE AND HAVE PLACED
PROB30S IN THE TAFS TO ACCOUNT FOR THIS. MVFR CEILINGS ARE
POSSIBLE IN SHOWERS MAINLY FROM REDUCED VISIBILITY BUT MVFR
CEILINGS ARE POSSIBLE AFTER 03 UTC.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...08
LONG TERM...08
AVIATION...COUSINS
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