Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 222028
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
328 PM CDT WED OCT 22 2014

.SYNOPSIS...
ISSUED AT 323 PM CDT WED OCT 22 2014

12Z UA ANALYSIS HAS AND UPPER HIGH OVER THE GREAT LAKES. A WEAK LLJ
RAN FROM THE HIGH PLAINS OF NEW MEXICO INTO NEBRASKA THAT WAS
PULLING MOISTURE NORTH AHEAD OF SHORTWAVE EXITING THE ROCKIES.
SATELLITE TRENDS SHOW THE CLOUDS IN CENTRAL IOWA SLOWLY EVAPORATING
AS THEY MOVE EAST BUT NEW CLOUDS WERE DEVELOPING ACROSS WESTERN IOWA.

18Z SFC ANALYSIS HAS THE SURFACE RIDGE FROM THE GREAT LAKES INTO THE
LOWER MISSISSIPPI VALLEY. A COLD FRONT RAN FROM THE EASTERN DAKOTAS
INTO NORTHEAST COLORADO. DEW POINTS WERE IN THE 30S AND 40S ACROSS
THE GREAT LAKES AND OHIO VALLEY WITH A PLUME OF DEW POINTS IN THE
50S AND LOW 60S FROM THE SOUTHERN PLAINS INTO THE EASTERN DAKOTAS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 323 PM CDT WED OCT 22 2014

QUIET AND DRY CONDITIONS WILL CONTINUE ACROSS THE AREA LATE THIS
AFTERNOON THROUGH MIDNIGHT AS HIGH PRESSURE SLOWLY MOVES INTO THE
EAST GREAT LAKES.

AFTER MIDNIGHT...MOISTURE AND CLOUDS WILL SLOWLY MOVE EASTWARD FROM
THE WESTERN HALF OF IOWA. FORCING WILL INCREASE WITH LIGHT RAIN
MOVING INTO THE WESTERN THIRD OF THE AREA BY SUNRISE. THE TRENDS IN
THE MODELS HAVE BEEN TO SLOW DOWN THE ARRIVAL OF THE RAIN SO THE
POTENTIAL IS THERE FOR FURTHER SLOWING. IF THIS OCCURS...THEN RAIN
MAY ONLY BE GETTING INTO THE EXTREME NORTHWEST AND WEST AREAS AROUND
SUNRISE.

THE PROLONGED PERIOD OF CLEAR SKIES WILL ALLOW TEMPERATURES TO DROP
INTO THE MID 30S IN THE FAR NORTHEAST/EAST AREAS WITH THE
POSSIBILITY OF TEMPERATURES NEAR FREEZING IN FAVORED LOW LYING AREAS.

ON THURSDAY...A BAND OF RAIN WILL MOVE ACROSS THE AREA FROM WEST TO
EAST. BASED ON THE OVERALL FORCING AND MOISTURE...THE THREAT OF RAIN
WILL ONLY BE FOR ABOUT 6 HOURS AT ANY GIVEN LOCATION WITH ABOUT 3-4
HOURS OF THAT TIME WITH THE HIGHEST POTENTIAL FOR RAIN.

AS SUCH...ROUGHLY THE EASTERN HALF OF THE AREA WILL STAY DRY UNTIL
LATE MORNING OR EARLY AFTERNOON. BY EARLY AFTERNOON...THE RAIN WILL
END ACROSS THE WESTERN QUARTER TO THIRD OF THE AREA AND AREAS WEST
OF THE MISSISSIPPI SHOULD BE DRY BY MID AFTERNOON. RAIN WILL LINGER
OVER THE FAR EASTERN AREAS INTO LATE AFTERNOON AND END BY SUNSET
THURSDAY.

RAINFALL AMOUNTS WILL BE AT BEST A QUARTER OF AN INCH OVER THE
WESTERN THIRD OF THE AREA. AREAS EAST OF THERE MAY SEE 0.1 TO 0.2
INCHES OF RAIN.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 323 PM CDT WED OCT 22 2014

THURSDAY NIGHT...ANY SHOWERS WILL BE EXITING FAR EASTERN CWA AROUND
00Z OR 7PM IF NOT EARLIER AS SHORTWAVE AND ATTENDANT FORCING QUICKLY
SHIFTS EAST. THIS WILL BE FOLLOWED BY CONTINUED CLEARING SKIES.
DESPITE DECREASE IN CLOUDS... LIGHT SOUTHWESTERLY WINDS AND WET
GROUND SHOULD PREVENT BIG DROP OFF IN TEMPS WITH LOWS MOST PLACES
ACTUALLY WARMER FROM WEDNESDAY NIGHT AND MAINLY IN THE RANGE OF 42-49F.

FRIDAY AND FRIDAY NIGHT...SOME CHANGES TO FORECAST AS MODELS NOW
CONVERGING ON SCENARIO OF WARM FRONTAL PASSAGE DURING THE AFTERNOON
AND EVENING. GOOD LOW TO MID LEVEL THETA-E ADVECTION WITH DECENT
LOW LEVEL MOISTURE GRADIENT WITH DEWPTS IN LOWER 50S TO LOWER 60S TO
AID IN TRANSIENT BAND OF LOW AND MID CLOUDINESS OVERSPREADING THE
CWA ON FRIDAY AND EXITING WEST TO EAST FRIDAY NIGHT WITH THE PASSAGE
OF THE FRONT. MOISTURE IS FAIRLY SHALLOW WITH DRY AIR ALOFT FAVORABLE
FOR DRIZZLE AND SOME MODELS ARE HINTING AT SOME VERY LIGHT NON-MEASURABLE
AMOUNTS OF PCPN. MAIN CHANGES WERE TO INCREASE SKY COVER... WHICH
MAY NEED FURTHER RAISING... AND TWEAK HIGHS DOWN A BIT ESPECIALLY WEST
OF THE MISSISSIPPI RIVER WHERE CLOUDS TO ARRIVE SOONER. MAY NEED TO
FURTHER TWEAK HIGHS DOWN AS MODEL TRENDS SEEM TO SUGGEST SLOWING OF WARM
FRONT AND ATTENDANT CLOUDS. FOR NOW THOUGH HAVE GENERAL RANGE OF HIGHS
FROM MID 60S TO AROUND 70 WITH WARMEST FAR WEST/SOUTHWEST WHERE TRYING
TO PUSH FRONT THROUGH AND BRING SOME DECREASE IN CLOUDS BY MID TO LATE
AFTERNOON. CLOUDS SHOULD CONTINUE SHIFTING EAST FRIDAY NIGHT EXITING
BY LATE EVENING WITH WARM FRONTAL PASSAGE. THIS WILL BE FOLLOWED BY
COOL FRONTAL PASSAGE OVERNIGHT EXITING SOUTHEAST EARLY SATURDAY MORNING.
LOWS FRIDAY NIGHT COOLEST NORTHWEST CWA (MID 40S) TO WARMEST SOUTHEAST
CWA (L50S).

SATURDAY THROUGH SUNDAY...SOME CHANGES MADE TO FORECAST FOR THESE PERIODS
AS WELL AS MODELS HAVE CONTINUED SLOWING THE MOVEMENT OF THE HIGH PRESSURE
AREA OVER THE WEEKEND. THIS DOES NOT MEAN ANY CHANGE TO NICE WEEKEND BEING
ADVERTISED... BUT IT DOES MEAN TEMPS NOT QUITE AS WARM WITH ABSENCE OF
SOUTHERLY WINDS AND WHILE COOLER IT WILL STILL BE AROUND NORMAL TO EVEN
A BIT ABOVE WITH HIGHS MAINLY IN THE 60S. WINDS WILL ALSO BE MUCH LESS OF
A FACTOR FOR SUNDAY WITH THE HIGH JUST EXITING SUNDAY MORNING... BUT SHOULD
SEE 10-20 MPH DURING AFTERNOON BUT DIRECTION FROM EAST AND SOUTHEAST WHICH
NOT FAVORABLE FOR MUCH WARMUP. MIN TEMPS SATURDAY NIGHT HAVE BEEN LOWERED
A COUPLE DEGS BUT WITH IDEAL RADIATIONAL COOLING SETUP THESE MAY NEED TO
BE FURTHER ADJUSTED DOWNWARD WITH MORE WIDESPREAD UPPER 30S POSSIBLE
CENTRAL AND NORTHEAST WITH 850 MB TEMPS AROUND 7-9C. SOME PATCHY SHALLOW
FOG WILL ALSO BE POSSIBLE LATE SATURDAY NIGHT WITH STEEP LOW LEVEL INVERSION.

EARLY NEXT WEEK...ALL MODELS SUPPORT A PERIOD OF WET WEATHER FOR THE
CWA WITH LONGWAVE TROUGH TRAVERSING THE MIDWEST. THE MAIN CHALLENGE IS
TIMING OF RAIN CHANCES AND AMOUNTS AS MODELS OFFER CONSIDERABLE AMOUNT OF
VARIANCE WITH STRENGTH OF ENERGY AND TIMING. HI-RES ECMWF CONTINUES TO BE
SLOWER AND DEEPER AND WOULD SUGGEST AFTER SOME RAIN CHANCES LATE SUNDAY NIGHT
NORTHERN CWA AHEAD OF WARM FRONT THEN MAINLY DRY AND QUITE MILD WARM SECTOR
FOR MONDAY WITH HIGHS IN THE 70-75F RANGE... WITH RAIN NOT ARRIVING UNTIL
LATER MONDAY NIGHT THROUGH WEDNESDAY IN THE FORM OF PERIOD OF FRONTAL RAIN
FOLLOWED BY SECONDARY SWATH OF MODERATE TO LOCALLY HEAVY RAINS WITH CLOSING
SOUTHERN STREAM ENERGY LIFTING THROUGH THE MID MISSISSIPPI VALLEY. GEM AND GFS
MORE PROGRESSIVE WITH TROUGH AND WEAKER WITH EMBEDDED ENERGY AND SUPPORTIVE
OF SUNDAY NIGHT THROUGH MONDAY AS MAIN WINDOW OF RAIN WITH MAINLY LIGHT
TO MODERATE AMOUNTS THEN COOLER/DRIER TUESDAY INTO WEDNESDAY. FORECAST IS
SOMEWHAT BLENDED APPROACH WITH RAIN CHANCES BEGINNING SUNDAY NIGHT NORTHERN
CWA AND ENTIRE CWA MONDAY INTO TUESDAY. TEMPS MILD MONDAY WITH HIGHS AROUND 70
TO L70S THEN TRENDING COOLER REST OF PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1229 PM CDT WED OCT 22 2014

VFR CONDITIONS WILL BE SEEN THROUGH 12Z/23 AS HIGH PRESSURE MOVES
INTO THE EASTERN GREAT LAKES AND A FRONT MOVES IN FROM THE
PLAINS. NO LLWS IS EXPECTED BUT 0-2KFT AGL SHEAR MAY APPROACH 20
KNOTS AT KCID/KDBQ IN THE HOURS JUST PRIOR AND AFTER SUNRISE. AFT
12Z/23 A BAND OF LIGHT RAIN WILL SLOWLY MOVE ACROSS EASTERN IOWA
INTO ILLINOIS BUT VFR CONDITIONS ARE EXPECTED TO CONTINUE.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08





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