773
FXUS63 KDVN 051047
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
547 AM CDT TUE MAY 5 2026
..UPDATED FOR 12Z AVIATION
KEY MESSAGES
- NORTHWEST FLOW ALOFT WILL KEEP TEMPERATURES COOLER THAN NORMAL
FOR THE WORK WEEK. A BRIEF WEEKEND WARM-UP WILL BE FOLLOWED BY
TEMPERATURES NEAR NORMAL NEXT WEEK.
- NUMEROUS UPPER LEVEL DISTURBANCES IN THE FLOW ALOFT HAVE THE
POTENTIAL TO BRING A DAILY RISK OF ISOLATED DIURNAL SHOWERS
WEDNESDAY THROUGH FRIDAY.
- A MORE SUBSTANTIAL UPPER LEVEL DISTURBANCE LOOKS TO BRING A
CHANCE OF RAIN TO THE AREA THE SECOND HALF OF THE WEEKEND.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 221 AM CDT TUE MAY 5 2026
VERY STRONG POST-FRONTAL FORCING WILL ALLOW A BAND OF ELEVATED
SHOWERS TO PERSIST THROUGH SUNRISE.
THE VERY SHORT TERM MODELS DEPICTS A SECOND BAND OF ELEVATED RAIN
THAT DEVELOPS ACROSS MISSOURI AND MOVES ACROSS THE SOUTHEAST HALF OF
THE AREA AFTER SUNRISE. THE POST-FRONTAL FORCING IS SUBSTANTIAL,
BUT, THE SUB-CLOUD LAYER IS EXTREMELY DRY SO THERE ARE QUESTIONS
REGARDING THE AREAL COVERAGE OF THIS BAND OF PRECIPITATION.
THE ECMWF-AIFS, AIGFS AND HREF-PMM SHOW THE ENTIRE AREA DRY TUESDAY
AND TUESDAY NIGHT AS DO A COUPLE OF THE DETERMINISTIC MODEL RUNS. A
DEEPER DIVE INTO THE MODELS SHOWS NORTH WINDS ALL THE WAY UP TO 5KFT
AGL. SO THE 30-40% POPS ACROSS THE SOUTHEAST HALF OF THE AREA TODAY
AND INTO THIS EVENING WERE INITIALLY THROUGH TO BE TRACEABLE TO SOME
OF THE WETTER ENSEMBLE MEMBERS. THE POPS ARE PROBABLY A RESULT OF
THE CURRENT BAND OF ELEVATED RAIN SHIFTING SOUTH. BASED ON REPORTING
VISIBILITIES WHERE IT IS RAINING, AMOUNTS WILL BE UNDER 0.05" WITH
MANY AREAS ONLY SEEING A TRACE.
AFTER MIDNIGHT TONIGHT DRY AND CHILLY CONDITIONS WILL BE SEEN AS
HIGH PRESSURE BUILDS INTO THE UPPER MIDWEST.
LONG TERM /WEDNESDAY THROUGH MONDAY/
ISSUED AT 221 AM CDT TUE MAY 5 2026
WEDNESDAY THROUGH FRIDAY NIGHT
ASSESSMENT...A CERTAINTY (>95%) OF COOLER THAN NORMAL
TEMPERATURES. LOW (<20%) CONFIDENCE ON RAIN CHANCES
NORTHWEST FLOW ALOFT WILL DOMINATE THE REMAINDER OF THE WORK-WEEK
WITH COOLER THAN NORMAL TEMPERATURES.
THE GLOBAL MODELS HAVE WEAK UPPER LEVEL DISTURBANCES PASSING THROUGH
ON A DAILY BASIS THAT HAVE THE POTENTIAL TO PRODUCE ISOLATED DIURNAL
RAIN SHOWERS IF SUFFICIENT MOISTURE IS AVAILABLE.
THE DISTURBANCES ON THURSDAY AND FRIDAY ARE STRONGER THAN THE
WEDNESDAY DISTURBANCE AND THUS MAY HAVE A LOW TO MEDIUM (20-40%)
PROBABILITY OF PRODUCING DIURNAL SHOWERS. INTERESTINGLY THE VARIOUS
MODELS AND THEIR RESPECTIVE ENSEMBLES DIFFER ON THE WEDNESDAY AND
THURSDAY DISTURBANCES. THE NET RESULT OF THIS DISAGREEMENT IS THAT
THE MODEL CONSENSUS KEEPS THURSDAY DRY WITH A VERY LOW (10-20%)
CHANCE OF RAIN ON WEDNESDAY.
WHERE THE MODELS ARE IN BETTER AGREEMENT IS WITH THE FRIDAY
DISTURBANCE. HERE THE MODEL CONSENSUS HAS A 15-30% CHANCE OF DIURNAL
SHOWERS.
THE KEY MESSAGE DURING THE WORK WEEK IS THAT ALTHOUGH THERE IS A
RISK OF RAIN, MANY LOCATIONS WILL REMAIN DRY AND THOSE AREAS THAT
SEE RAIN WILL HAVE MANY HOURS OF DRY WEATHER.
SATURDAY
ASSESSMENT...MEDIUM TO HIGH (60-80%) CONFIDENCE OF WARMER
TEMPERATURES
THE NORTHWEST FLOW BRIEFLY BECOMES MORE ZONAL ON SATURDAY ALLOWING
TEMPERATURES TO SURGE ABOVE NORMAL. THERE IS A WEAK UPPER LEVEL
DISTURBANCE THAT WILL MOVE THROUGH THE AREA, BUT, ATMOSPHERIC
PROFILES ARE VERY DRY SO THE DISTURBANCE SHOULD ANNOUNCE ITSELF WITH
AN INCREASE IN CLOUDS.
SATURDAY NIGHT THROUGH SUNDAY NIGHT
ASSESSMENT...HIGH (>80%) CONFIDENCE OF A COOL DOWN TO NEAR NORMAL
TEMPERATURES. LOW TO MEDIUM (20-40%) CONFIDENCE ON RAIN CHANCES.
THE VARIOUS GLOBAL MODELS HAVE A RESPECTABLE SYSTEM PROGGED TO MOVE
THROUGH THE MIDWEST. HOWEVER, THERE ARE DIFFERENCES ON TIMING AND
TRACK OF THE SYSTEM. DEPENDING UPON THE MODEL SOLUTION, THE GULF IS
EITHER PARTIALLY OPEN AND SUPPLYING MOISTURE, OR, THE MOISTURE IS
TAKING THE LONGER TRACK THROUGH MEXICO.
THERE APPEARS TO BE REASONABLE AGREEMENT THAT THE BETTER CHANCES FOR
RAIN LOOK TO BE LATE SATURDAY NIGHT AND SUNDAY MORNING. HERE THE
MODEL CONSENSUS HAS 30-50% POPS. EITHER SIDE OF THOSE TIMES ARE 20-
30% POPS.
THE ONLY CONCERN IS THE SYSTEM MAY TRACK FURTHER SOUTH THAN
CURRENTLY FORECAST. GIVEN THE STRENGTH OF THE PROGGED UPPER LOW OVER
THE NORTHERN GREAT LAKES THAT IS A LEGITIMATE CONCERN.
INTERESTINGLY, THE ECMWF-AIFS AND AIGFS ONLY SHOW RAIN LATE SATURDAY
NIGHT WITH SUNDAY/SUNDAY NIGHT DRY.
MONDAY
ASSESSMENT...MEDIUM TO HIGH (60-80%) CONFIDENCE ON NEAR NORMAL
TEMPERATURES
STARTING EARLY NEXT WEEK THE WESTERN RIDGE BUILDS SLIGHTLY ALLOWING
THE NORTHWEST FLOW T BECOME SLIGHLY MORE AMPLIFIED. TEMPERATURES
WILL BE CLOSE TO NORMAL, BUT, THERE IS YET ANOTHER UPPER LEVEL
DISTURBANCE PROGGED TO MOVE THROUGH IN THE FLOW ALOFT. AGAIN,
PROGGED ATMOSPHERIC PROFILES ARE QUITE DRY SO ONLY AN INCREASE IN
CLOUDS SHOULD MARK THE PASSAGE OF THE DISTURBANCE.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 540 AM CDT TUE MAY 5 2026
POST-FRONTAL LIGHT SHOWERS WITH VISIBILITY >6SM AND CEILINGS 6-10KFT AGL
WILL BE FOUND NEAR THE KMLI AND KBRL TERMINALS AT TIMES DURING THE
PERIOD. OTHERWISE, CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGHOUT AT
ALL OF THE TERMINALS. WINDS MAY BECOME LIGHT AND VARIABLE FOR A WHILE
THIS MORNING, BEFORE INCREASING TO AROUND 10+ KT FROM THE NORTH/NORTHWEST
LATE MORNING AND AFTERNOON WITH SPORADIC HIGHER GUSTS 15-18+ KT POSSIBLE.
WINDS WILL BE LIGHT NORTHERLY OR VARIABLE TONIGHT AROUND THE PASSAGE OF A
SURFACE TROUGH.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...08
LONG TERM...08
AVIATION...MCCLURE
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