461
FXUS63 KDVN 140553
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1253 AM CDT WED APR 14 2021
..06Z AVIATION UPDATE
UPDATE
ISSUED AT 830 PM CDT TUE APR 13 2021
HAVE EXPANDED THE FROST ADVISORY TO INCLUDE THE I-80 CORRIDOR.
LATEST SATELLITE TRENDS SHOW THE STRATUS INTO NORTHERN IOWA MOVING
MORE LATITUDINAL THAN LONGITUDINAL, AND WOULD SUPPORT SOME OF THE
RECENT GUIDANCE IN KEEPING THE I-80 CORRIDOR, WHICH HAS SOME
SUSCEPTIBLE VEGETATION, LARGELY ABSENT OF THIS THERMALLY
IMPACTFUL CLOUDINESS. SOME CIRRUS WILL BE PRESENT, BUT SATELLITE
SHOWS THIS TO BE RATHER THIN AND SHOULD BE LIMITED IN IMPACTS TO
TEMPERATURES. WITH 850 MB TEMPERATURES PROGGED BACK DOWN TO AROUND
-5C TO -6C TOMORROW MORNING, ANTICIPATE LOWS NEAR TO A BIT BELOW
THOSE FROM THIS MORNING IN MOST AREAS AND AROUND 30-36F. FAR
NORTHERN SECTIONS, ESPECIALLY IN EASTERN IOWA, LOWS ARE A BIT
TRICKY AS THE STRATUS MAY EVENTUALLY WORK SOUTHWARD AND OFFER
PERIODIC BOUTS OF CLOUDINESS. THUS, IT LOOKS LIKE THERE IS THE
POTENTIAL TO BE A BIT WARMER THAN FORECAST INTO PORTIONS OF
NORTHEAST IOWA.
SYNOPSIS
ISSUED AT 244 PM CDT TUE APR 13 2021
ANOTHER GREAT DAY WAS UNFOLDING ACROSS ALL OF EASTERN IOWA,
NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI, WITH THE AREA UNDER
INFLUENCE FROM HIGH PRESSURE RIDGING EXTENDING FROM THE CENTRAL
GREAT PLAINS INTO THE OHIO RIVER VALLEY. SKIES FEATURED A MIX OF SUN
AND CLOUDS, WITH SOMEWHAT COOL TEMPERATURES ATYPICAL FOR MID-APRIL.
VALUES AS OF 2 PM RANGED FROM 47 IN DUBUQUE, TO 57 IN KEOKUK.
SHORT TERM
(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 244 PM CDT TUE APR 13 2021
KEY MESSAGES:
1) PATCHY TO AREAS OF FROST TONIGHT, WITH IMPACTS LIKELY MAINLY
SOUTH OF I-80.
2) A CHANCE FOR PM SPRINKLES WEDNESDAY, BUT MOST WILL REMAIN DRY.
COOL TEMPERATURES CONTINUE.
HIGH PRESSURE WILL REMAIN IN CONTROL OF OUR WEATHER FOR THROUGH
WEDNESDAY, MEANING QUIET WEATHER WITH MAINLY DRY CONDTIONS ARE
EXPECTED. THE ONLY EXCEPTION WILL AREAS OF EASTERN IOWA AND
NORTHWEST ILLINOIS MAINLY NORTH OF I-80 WEDNESDAY AFTERNOON, WHERE
THERE WILL BE A CHANCE OF SPRINKLES. SEVERAL CAMS INCLUDING THE
NAMNEST AND HRRR ARE ON BOARD WITH THIS IDEA AS AN AREA OF CVA
ROTATES AROUND THE SOUTHERN PORTION OF A 500 HPA LOW CENTERED OVER
THE GREAT LAKES. THESE WILL BE SCATTERED IN NATURE, WITH MUCH OF
LIKELY REMAINING DRY THROUGH THE DAY.
THE MORE PRESSING CONCERN WILL BE THE THREAT OF FROST TONIGHT, WHICH
LOOKS LIKELY WITH LIGHT WINDS, CLEAR SKIES AND A COOL AIR MASS IN
PLACE ACROSS PARTS OF THE AREA. AFTER COORDINATING WITH
SURROUNDING OFFICES, WENT AHEAD AND ISSUED A FROST ADVISORY FOR
COUNTIES ALONG AND SOUTH OF HWY 34 IN SOUTHEAST IOWA, WEST CENTRAL
ILLINOIS AND FAR NORTHEAST MISSOURI. THIS AREA IS MOST
SUSCEPTIBLE ACROSS THE CWA WITH REGARDS TO VEGETATION.
TEMPERATURES ARE EXPECTED TO FALL INTO THE LOW TO MID 30S HERE.
ELSEWHERE, TEMPERATURES WILL BE COLD WITH VALUES DROPPING TO NEAR 30
ALONG THE HWY 20 CORRIDOR. WITH NO SUSCEPTIBLE VEGETATION HERE
DID NOT GO AHEAD WITH FROST/FREEZE HEADLINES. HIGHS TOMORROW WILL
CONTINUE TO BE COOL WITH VALUES IN THE UPPER 40S/LOW 50S.
LONG TERM
(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 244 PM CDT TUE APR 13 2021
KEY MESSAGES:
1) BELOW NORMAL TEMPERATURES CONTINUE.
2) MAINLY DRY THROUGH THE WEEKEND; PRECIPITATION CHANCES INCREASE
NEXT WEEK.
3) POTENTIAL FOR FROST AGAIN WEDNESDAY NIGHT/THURSDAY MORNING.
WEDNESDAY NIGHT AND THURSDAY MORNING WILL ONCE AGAIN BE MONITORED
FOR FROST/FREEZE POTENTIAL AS ANOTHER NIGHT OF COLD TEMPERATURES IS
EXPECTED. WHILE TEMPERATURES ARE FORECAST TO NOT BE AS COLD AS
TONIGHT, VALUES IN THE LOW 30S WILL BE MORE WIDESPREAD. WILL MONITOR
FOR POTENTIAL FOR MORE HEADLINES TOMORROW.
OTHERWISE, MOST OF THE LONG TERM PERIOD WILL FEATURE MAINLY DRY
CONDITIONS AND CONTINUED COOL TEMPERATURES WITH THE DOMINANT FLOW
PATTERN EXPECTED TO REMAIN OUT OF THE NORTHWEST. DAILY HIGHS IN THE
50S TO NEAR 60 ARE EXPECTED, WITH OVERNIGHT LOWS IN THE 30S TO LOW
40S.
CHANCES FOR PRECIPITATION ARE MAINLY FAVORED FRIDAY NIGHT AND
SATURDAY AS A WEAK SHORTWAVE PASSES ACROSS THE AREA TO THE SOUTH.
MODELS ARE IN DISAGREEMENT OF INTENSITY, WITH THE GFS SUGGESTING
MORE OF A MOISTURE DRAW, STRONGER LIFT AND THUS A HIGHER QPF FOR OUR
SOUTHEAST IOWA, WEST CENTRAL ILLINOIS AND NORTHEAST MISSOURI
COUNTIES. HOWEVER, THIS LOOKS TO BE THE OUTLIER OF GUIDANCE, SO WILL
PLAY MORE ON THE CONSERVATIVE END WITH JUST A SLIGHT CHANCE TO
CHANCE OF POPS. THIS IS FAVORED OVER OUR SOUTHEAST IOWA, WEST
CENTRAL ILLINOIS AND NORTHEAST MISSOURI COUNTIES.
THERE IS AGREEMENT THAT A COLD FRONT APPROACHING THE AREA WILL BE
THE DRIVER FOR OUR NEXT CHANCE OF PRECIPITATION, WHICH LOOKS TO BE
FAVORED NEXT MONDAY/MONDAY NIGHT. NBM HAS INTRODUCED SLIGHT
CHANCE POPS WITH THIS RUN, AND I THINK THAT'S A GOOD STARTING
POINT CONSIDERING WE HAVE PLENTY OF TIME FOR THINGS TO GET MORE
REFINED IN THE GUIDANCE.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1246 AM CDT WED APR 14 2021
VFR CONDITIONS WITH RATHER LIGHT WEST TO NORTHWEST SFC WINDS
OVERNIGHT, THAT UNTIL TIMING A MVFR BKN OR EVEN OVC STRATOCU DECK
ROTATING DOWN ACRS MOST OF THE TERMINALS WED MORNING. ONLY BRL
MAYBE SPARED FROM THE MVFR DECK, AS IT ADVECTS ACRS THE REST OF
THE TERMINALS FROM MID MORNING THROUGH EARLY AFTERNOON. SOME
LIFTING OF THE DECK TO LOW VFR LEVELS(ABOVE 3K FT AGL) AT TIMES
INTO WED EVENING. SOME ISOLATED TO WIDELY SCTRD INSTABILITY
SHOWERS WILL LOOK TO POP UP IN THE MID TO LATE AFTERNOON PERIOD
MAINLY ALONG AND NORTH OF HWY 30, BUT COVERAGE UNCERTAINTY
PRECLUDES TAF MENTION OR EVEN A VCNTY AT THIS TIME. WEST TO
NORTHWEST SFC WINDS WILL INCREASE AGAIN MID TO LATE WED MORNING
10-15 KTS WITH HIGHER GUSTS. ..12..
DVN WATCHES/WARNINGS/ADVISORIES
IA...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR CEDAR-DES MOINES-
HENRY IA-IOWA-JEFFERSON-JOHNSON-KEOKUK-LEE-LOUISA-MUSCATINE-
SCOTT-VAN BUREN-WASHINGTON.
IL...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR BUREAU-HANCOCK-
HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-
WARREN.
MO...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR CLARK-SCOTLAND.
UPDATE...MCCLURE
SYNOPSIS...SPECK
SHORT TERM...SPECK
LONG TERM...SPECK
AVIATION...12
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