751
FXUS63 KDVN 300542
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1242 AM CDT SUN MAR 30 2025
KEY MESSAGES
- THE SEVERE RISK ON SUNDAY HAS SHIFTED SLIGHTLY EAST. WHILE THE
LEVEL 1 AND 2 OUT OF 5 RISKS REMAIN, THE SEVERE RISK AREA
LOOKS TO BE ALONG AND EAST OF THE MISSISSIPPI RIVER. THE
PRIMARY RISKS ARE DAMAGING WINDS AND HAIL.
- THE ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH NEXT WEEK
WITH ADDITIONAL SYSTEMS MOVING THROUGH THE MIDWEST.
- TEMPERATURES WILL RISE ABOVE NORMAL AHEAD OF APPROACHING
SYSTEM AND THEN FALL BELOW NORMAL BEHIND EACH SYSTEM.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 254 PM CDT SAT MAR 29 2025
THROUGH THE LATE AFTERNOON AND EARLY EVENING SOME ISOLATED SHOWERS
OR SPRINKLES ARE POSSIBLE. A LARGE MAJORITY OF THE AREA WILL REMAIN
DRY. THE COLD FRONT WILL CONTINUE TO SAG SOUTH BEFORE STALLING
BETWEEN HIGHWAYS 20 AND 30.
BY LATE EVENING AND CONTINUING OVERNIGHT THE FIRST UPPER LEVEL
IMPULSE MOVES INTO THE AREA. THIS IMPULSE COMBINED WITH 25-30 KNOT
LLJ SHOULD BE ENOUGH TO INDUCE ISOLATED TO SCATTERED (20-40%)
SHOWERS AND SOME THUNDERSTORMS WITH THE BETTER COVERAGE WEST OF THE
MISSISSIPPI. GIVEN THE FREEZING LEVELS ALOFT, THE STRONGER SHOWERS
AND THUNDERSTORMS WOULD BE CAPABLE OF PRODUCING COPIOUS AMOUNTS OF
VERY SMALL HAIL. WHILE THE OVERALL PROBABILITY IS NO GREATER THAN 15
PERCENT, A ROGUE THUNDERSTORM COULD PRODUCE SOME HAIL UP TO 1 INCH.
AT SUNRISE SUNDAY A SECONDARY UPPER LEVEL DISTURBANCE SHOULD PUSH A
BAND OF RAIN WITH EMBEDDED THUNDERSTORMS THROUGH THE AREA. THIS
SECONDARY UPPER LEVEL DISTURBANCE LOOKS TO BE THE RESULT OF A
NOCTURNAL CONVECTIVE COMPLEX THAT DEVELOPS IN THE PLAINS AND RACES
NORTHEAST ACROSS MISSOURI. ONCE THIS DISTURBANCE PASSES THROUGH THE
AREA, DOWNWARD MOTION IN THE ATMOSPHERE BEHIND IT COULD SUPPRESS ANY
NEW CONVECTION WEST OF THE MISSISSIPPI DURING THE AFTERNOON.
THE BOUNDARIES PUT OUT BY THE SECOND DISTURBANCE AND STRENGTH OF THE
DOWNWARD MOTION BEHIND IT WILL BE THE KEY AS TO WHERE THE DIURNAL
SEVERE STORMS DEVELOP ON SUNDAY.
DATA FROM THE VERY HIGH RESOLUTION MODELS ARE GENERALLY POINTING TO
AREAS EAST OF THE MISSISSIPPI FOR SEVERE STORMS SUNDAY AFTERNOON,
WHICH, IS A TAD FARTHER EAST THAN WHAT WAS SUGGESTED YESTERDAY.
ONE OR TWO SOLUTIONS ARE SUGGESTING ALONG/EAST OF THE ILLINOIS
RIVER WITH CONVECTION SUPPRESSED ACROSS EASTERN IOWA AND WEST
CENTRAL ILLINOIS.
MESO-BETA AND GAMMA SCALES WILL BE KEY PLAYERS FOR STORM
DEVELOPMENT SUNDAY AFTERNOON. TAKING INTO ACCOUNT MODEL ERRORS,
AN EDUCATED GUESS WOULD PUT THE INITIATION POINT FOR THE DIURNAL
SEVERE STORMS BETWEEN THE MISSISSIPPI AND ILLINOIS RIVERS
SHORTLY AFTER MID-DAY SUNDAY. STORMS WOULD THEN QUICKLY GROW
UPSCALE INTO A BROKEN LINE AND MOVE EAST.
IF THIS SCENARIO IS CORRECT, THE OVERALL WINDOW FOR SEVERE STORMS IN
OUR EASTERN HALF WOULD BE FAIRLY NARROW AT 4 TO 5 HOURS.
SUNDAY NIGHT COLD AIR WILL GET RAPIDLY PULLED INTO THE AREA BEHIND
THE DEPARTING STORM. SHOWERS WILL CONTINUE DURING THE EVENING WITH
THE RAIN CHANGING OVER TO ALL SNOW BEFORE ENDING AFTER MIDNIGHT.
DUE TO THE WARMTH THE GROUND AND ROADS HAVE ABSORBED, ANY SNOW WILL
MELT ON CONTACT WITH ONLY A LIGHT DUSTING ON ELEVATED SURFACES.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 254 PM CDT SAT MAR 29 2025
MONDAY/MONDAY NIGHT
ASSESSMENT...HIGH CONFIDENCE ON COOLER BUT DRY CONDITIONS
THE MODEL CONSENSUS HAS A CANADIAN HIGH MOVING THROUGH THE MIDWEST
WITH COOLER THAN NORMAL TEMPERATURES FOR EARLY APRIL. ATTENTION THEN
TURNS TO THE NEXT SYSTEM.
TUESDAY THROUGH WEDNESDAY NIGHT
ASSESSMENT...HIGH CONFIDENCE ON ANOTHER STORM SYSTEM
THE OVERALL FLOW PATTERN REMAINS VERY CONDUCIVE FOR STRONG
EXTRATROPICAL STORM SYSTEMS AND THE GLOBAL MODELS HAVE BEEN
ADVERTISING A MID-WEEK SYSTEM FOR THE PAST SEVEN DAYS.
WHILE THERE ARE TIMING AND TRACK DIFFERENCES BETWEEN THE INDIVIDUAL
MODELS, THERE IS LOOSE AGREEMENT THAT TUESDAY NIGHT INTO WEDNESDAY
MORNING IS PRIME TIME FOR RAIN. THE PROBABILITIES FOR RAIN ARE:
20-40% TUESDAY AFTERNOON, 80-90% TUESDAY NIGHT, 50-80%
WEDNESDAY AND 20% WEDNESDAY EVENING.
THIS TIMING IS SLIGHTLY FASTER THAN PREVIOUS RUNS AND MAY OR MAY NOT
BE AN ANOMALY. IF THE FASTER TIMING PROVES TO BE CORRECT, THEN WHILE
STORMS WILL BE SEEN, THE STRENGTH OF THOSE STORMS WOULD BE IN
QUESTION.
SPC ALREADY HAS THE AREA HIGHLIGHTED IN A SLIGHT RISK OF SEVERE
STORMS ON WEDNESDAY BASED ON THE LARGE SCALE SYNOPTIC FEATURES.
WHILE THE SYNOPTIC SCALE FEATURES PRIME THE AREA, IT WILL BE THE
MESOSCALE (20-200 KM) FEATURES THAT WILL DICTATE WHEN AND WHERE
ANY SEVERE STORMS DEVELOP. THE CURRENT FASTER MOVEMENT OF THE
LARGE SCALE SYSTEM SUGGESTS THE HIGHER PROBABILITY OF STORMS
BEING TUESDAY NIGHT INTO WEDNESDAY MORNING WHICH, IF CORRECT,
WOULD REMOVE THE DIURNAL HEATING ASPECT USUALLY NEEDED TO
GENERATE SEVERE STORMS. HOWEVER, SOME OF THE LARGER SCALE
FEATURES THAT CAN BE RESOLVED THIS FAR OUT DO SUPPORT THE
POTENTIAL FOR SEVERE STORMS.
REGARDLESS, TUESDAY NIGHT INTO WEDNESDAY WILL NEED TO BE WATCHED
CAREFULLY FOR THE OVERALL SEVERE RISK.
THURSDAY THROUGH SATURDAY
ASSESSMENT...MEDIUM CONFIDENCE ON RAIN CHANCES
THE GLOBAL MODELS HAVE A WEAK SYSTEM BRUSHING ACROSS THE SOUTHERN
HALF OF THE AREA. MOISTURE AVAILABILITY IS IN QUESTION REGARDING THE
CHANCES FOR RAIN BUT THE MODEL CONSENSUS HAS A 20 PERCENT CHANCE
THURSDAY/THURSDAY NIGHT.
THE GLOBAL MODELS HAVE WEAK BUT BETTER ESTABLISHED SYSTEM PROGGED TO
MOVE THROUGH THE MIDWEST LATE FRIDAY AFTERNOON INTO FRIDAY NIGHT.
THERE ARE MINOR TIMING DIFFERENCES BUT FRIDAY NIGHT HAS THE BETTER
CHANCES FOR RAIN, CURRENTLY AT 20-40 PERCENT. RAIN THAT DEVELOPS
FRIDAY NIGHT WILL LINGER INTO SATURDAY MORNING BEFORE ENDING.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1242 AM CDT SUN MAR 30 2025
A COMPLICATED TAF FORECAST IS ON TAP FOR TODAY AS AN AREA OF
LOW PRESSURE CURRENTLY OVER SOUTH-CENTRAL IOWA APPROACHES THE
AREA. A STATIONARY FRONT REMAINS DRAPED OVER OUR NORTHERN
FORECAST AREA, WITH NORTHEAST WINDS AND MVFR TO IFR CEILINGS
BEING REPORTED AT DBQ. FARTHER SOUTH, SOUTHEASTERLY WINDS REMAIN
IN PLACE. ADDITIONALLY, A FEW ROUNDS OF SHOWERS AND
THUNDERSTORMS ARE POSSIBLE TONIGHT INTO SUNDAY MORNING: 1)
BETWEEN 07Z AND 11Z THIS MORNING FOR CID AND DBQ, AND 2) BETWEEN
13Z TO 15Z FOR BRL AND MLI. OVERALL, HIGH-RES MODELS ARE IN
DECENT AGREEMENT IN THE TIMING AND COVERAGE OF THIS ACTIVITY,
BUT STILL SOME SUBTLE DIFFERENCES EXIST. SOME OF THE STRONGER
STORMS WILL BE CAPABLE OF LOCALLY STRONG WINDS (GUSTS POSSIBLY
UP TO AROUND 40 KNOTS), BUT THESE SHOULD REMAIN ISOLATED.
AS THE LOW APPROACHES, MVFR TO IFR CEILINGS SHOULD EXPAND ACROSS
THE AREA, ALONG WITH WINDS GRADUALLY TURNING MORE NORTHWESTERLY
AND STRENGTHENING AS COLDER AIR FILTERS IN BEHIND IT. GUSTS
BETWEEN 20 TO 25 KNOTS WILL BE COMMON. ANOTHER ROUND OF
PRECIPITATION IS POSSIBLE THIS EVENING, MAINLY ACROSS OUR FAR
NORTH, WHERE SOME LIGHT SNOW IS POSSIBLE AT DBQ.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...08
LONG TERM...08
AVIATION...SCHULTZ
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