Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 210906
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
406 AM CDT TUE APR 21 2015

.SYNOPSIS...
ISSUED AT 355 AM CDT TUE APR 21 2015

UPPER LOW WAS PARKED NEAR THE ARROWHEAD OF MN EARLY THIS AM WITH
CWA RESIDING IN COOL NORTHWEST FLOW. FAST MOVING DISTURBANCE
DIVING SOUTHEAST THROUGH ND WILL BE PASSING LATER THIS AFTN/EVE
ACCOMPANIED BY CHANCE OF SHOWERS MAINLY ACROSS THE SOUTHERN COUNTIES.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT TUE APR 21 2015

WINDS... TEMPS AND PCPN CHCS MAIN FCST ISSUES. CLOSED LOW WILL MEANDER
SLOWLY EASTWARD THROUGH THE GREAT LAKES NEXT 24 HOURS WITH CWA
REMAINING IN COOL NORTHWEST FLOW. EXPECT ANOTHER WINDY DAY DUE TO
DEEP MIXING WITH 30-35+KTS AVERAGE THROUGH MIXED LAYER AND 45-55KTS
SITTING ATOP. TAKING ROUGHLY 80 PERCENT OF THESE WINDS AND ALSO
WINDS AT 850 MB IN SUPER-ADIABATIC CONDITIONS YIELDS WINDS FLIRTING
WITH ADVISORY CRITERIA AT TIMES WITH SUSTAINED NEAR 30 MPH AND GUSTS
40-45 MPH. HIGHEST WINDS FAVOR MUCH OF CWA NEAR/NORTH OF HWY 34
PER H5-H3 POTENTIAL VORTICITY AND TROP PRESSURE... THUS HAVE ISSUED
A WIND ADVISORY FOR MUCH OF THE AFFORMENTIONED AREA NORTH OF HWY 34
FROM 16Z-00Z. IF MORE CLOUDINESS NORTH AND EARLIER ARRIVAL THEN COULD
LIMIT WINDS BELOW CRITERIA... AND THIS WOULD OF MOST CONCERN ALONG THE
HWY 20 CORRIDOR. COULD ALSO SEE A FEW PM SHOWERS NEAR/NORTH OF HWY 20
CORRIDOR WITH SPOKE OF ENERGY SHEARING ON BACKSIDE OF UPPER LOW. MAIN
FOCUS FOR SHOWERS APPEARS WITH ENERGY PACKET DIVING SOUTHEAST THROUGH ND.
DESPITE LIMITED MOISTURE... ENOUGH FORCING WITH SUPPORT FROM DIVERGENCE
WITH JET STREAK AND MID LEVEL VORTICITY ADVECTION FOR CHANCE OF
SHOWERS LATE THIS AFTN/EVE MAINLY SOUTH OF I-80. AS FOR TEMPS...COOL
CYCLONIC FLOW WILL KEEP READINGS BELOW NORMAL WITH HIGHS FROM
AROUND 50/LOWER 50S NORTH TO LOWER 60S SOUTH. LOWS TONIGHT WIDESPREAD 30S.
WINDS WILL CONTINUE TO SLOWLY DIMINISH TONIGHT BUT APPEARS AT THIS
TIME ENOUGH OF GRADIENT TO KEEP BL MIXED FOR LIMITED FROST POTENTIAL
TONIGHT.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE APR 21 2015

FORECAST FOCUS ON BELOW NORMAL TEMPERATURES WITH A PERSISTENT
NORTHWEST FLOW ALOFT AS SPRING APPEARS TO TAKE A VACATION. FROST AND
FREEZING TEMPERATURES SEEM LIKELY WEDNESDAY NIGHT AND POSSIBLY AGAIN
THURSDAY NIGHT. LOW CONFIDENCE ON POTENTIAL FOR RAIN BY THIS WEEKEND.

WEDNESDAY THROUGH THURSDAY NIGHT...A CHILLY PERIOD WITH WELL BELOW
NORMAL TEMPERATURES WITH FROST/FREEZE LIKELY WEDNESDAY NIGHT...AND
POSSIBLY AGAIN THURSDAY NIGHT. HIGH PRESSURE RIDGE WILL EXTEND FROM
THE NORTHERN PLAINS INTO THE OHIO VALLEY...BRINGING MAINLY CLEAR
SKIES AND RATHER LIGHT WINDS. WITH 850 MB TEMPERATURES DIPPING TO 0C
TO -4C SEEMS REASONABLE TO BE CONCERNED WITH A FROST/FREEZE. MAXIMUM
TEMPERATURES WILL BE IN THE 50S TO AROUND 60 BOTH WEDNESDAY AND
THURSDAY. LOW TEMPERATURES WEDNESDAY NIGHT SHOULD DROP INTO THE
UPPER 20S TO LOWER 30S AT MANY LOCATIONS. SOME FAVORED VALLEY AND
LOW LYING AREAS MAY BE EVEN COLDER. BY THE TIME WE GET TO THURSDAY
NIGHT THE MODELS WANT TO SHIFT THE RIDGE A BIT TO THE NORTHEAST.
THIS WOULD FAVOR OUR NORTHEAST HALF FOR ANOTHER POTENTIAL NIGHT OF
FROST/FREEZE EVENT. BUT...IF THE RIDGE REMAINS OVER THE DVN CWA THEN
THE ENTIRE CWA WOULD BE AT RISK FOR FROST. I HAVE NOT INTRODUCED
FROST IN THE GRIDS YET BUT WILL CONTINUE TO MENTION IN THE HWO
PRODUCT. GARDENERS AND NURSERIES WILL WANT TO PAY CLOSE ATTENTION TO
THE FORECAST OVER THE NEXT DAY OR TWO.

FRIDAY THROUGH MONDAY...THE ECMWF SUGGESTS AN ACTIVE NORTHWEST FLOW
PATTERN BUT THE GFS WOULD SAY OTHERWISE. THEREFORE...CONFIDENCE IS
LOW DUE TO SIGNIFICANT MODEL DISCREPANCIES. THE ECMWF BRINGS A DEEP
TROUGH IN THE SOUTHERN STREAM WITH LOW PRESSURE TRACKING INTO THE
MID MS VALLEY. THIS MODEL INDICATES A DECENT WIDESPREAD RAINFALL FOR
THE DVN CWA ARRIVING ON FRIDAY AND CONTINUING THROUGH SATURDAY...
WITH ANOTHER TROUGH AND MORE WET WEATHER ON MONDAY. HOWEVER...THE
GFS IS MUCH WEAKER WITH THE SYNOPTIC FEATURES AND KEEPS THE RAIN
MAINLY NORTH AND SOUTH OF THE DVN CWA. WITH A NORTHWEST FLOW AND
VERY DRY AIR LURKING NEARBY IT WILL BE INTERESTING TO SEE HOW THIS
PLAYS OUT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1152 PM CDT MON APR 20 2015

VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD. EXPECT AN
INCREASING W/NW LATE TUESDAY AM...ESPECIALLY AT KCID/KDBQ...WITH
DIURNAL STRATOCUMULUS. AN AREA OF SHOWERS IS EXPECTED NEAR KBRL
TUESDAY EVENING...AND HAVE INCLUDED A VCSH GROUP BEGINNING AT 01Z.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING
     FOR BENTON-BUCHANAN-CEDAR-CLINTON-DELAWARE-DES MOINES-
     DUBUQUE-IOWA-JACKSON-JOHNSON-JONES-LINN-LOUISA-MUSCATINE-
     SCOTT.

IL...WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING
     FOR BUREAU-CARROLL-HENDERSON-HENRY IL-JO DAVIESS-MERCER-
     PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.

MO...NONE.
&&

$$

SYNOPSIS...05
SHORT TERM...05
LONG TERM...HAASE
AVIATION...RP KINNEY


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