Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 220423
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1123 PM CDT MON JUL 21 2014

.SYNOPSIS...
ISSUED AT 228 PM CDT MON JUL 21 2014

FAIR SKIES AND SOUTH WINDS AHEAD OF A DEVELOPING COOL FRONT IN THE
NORTHERN HIGH PLAINS IS ALLOWING FOR TEMPERATURES TO RISE INTO THE
LOWER TO MIDDLE 80S OVER THE FORECAST AREA AT 2 PM. UPPER AIR AND
SURFACE ANALYSIS SHOWS COOL AIR BEHIND FRONT IS AS STRONG OR STRONGER
THAN SOLUTIONS...WHICH HAS BEEN THE CASE MOST OF THIS YEAR. THIS
SUPPORTS SUBSIDENCE TONIGHT AHEAD OF FRONT AND SURFACE DEWPOINTS
AT 2 PM ARE TRENDING 1-3 DEGREES LOWER THAN AMERICAN SOLUTIONS.
UPSTREAM ENERGY AT 18Z VERIFIES AS STRONG OR STRONGER FOR A SEASONALLY
STRONG COOL FRONTAL PASSAGE LAT TUESDAY AND TUESDAY NIGHT. LOTS OF JET
ENERGY UPSTREAM OVER NORTH PACIFIC ENSURES BELOW NORMAL TO WELL BELOW
NORMAL TEMPERATURES NEXT 7 PLUS DAYS AFTER COOL FRONT PASSES TUESDAY
NIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 228 PM CDT MON JUL 21 2014

TONIGHT...WARM TO MILD WITH LIGHT SOUTH WINDS OF 5 TO 10 MPH UNDER A
FAIR SKY. HAVE KEPT DRY WITH CAP IN PLACE AND LITTLE OR NO FORCING AHEAD
OF COOL FRONT GATHERING STRENGTH IN THE PLAINS. LOCAL TOOLS SUGGEST
MINS UPPER 60S IN ILLINOIS...AROUND 70 ALONG THE MISSISSIPPI RIVER AND
LOWER 70S EASTERN IOWA.

TUESDAY...PERSISTENCE AND TRENDS SUGGEST SLIGHTLY COOLER WITH RISK OF
DEBRIS CLOUDS POSSIBLE FROM UPSTREAM CONVECTION AND ENERGY. THIS SUGGESTS
MARGINAL HEAT ADVISORY RISK OVER SW TO W 1/3 TO 1/2 OF AREA FOR A FEW
TO POSSIBLY AS MUCH AS 4 TO 5 HOURS FAR SOUTHWEST. SIGNIFICANT UNCERTAINTY
AND RISK OF DEBRIS CLOUDS...WILL PASS TO NIGHT SHIFT AS THEY WILL BE
ABLE TO BETTER ASCERTAIN THE NEED FOR A HEAT ADVISORY AS CLOUD DEBRIS
ISSUE WILL ALSO BE BETTER KNOWN. THE KEY IN THIS WILL BE A MARGINAL
HEAT ADVISORY FOR LOCATIONS THAT DO REACH ADVISORY CRITERIA...COUPLED
WITH SW TO SSW WINDS OF 10 TO 20+ MPH. HIGHS SHOULD BE 88 TO 94 DEGREES
NE TO SW OVER THE AREA. PERSISTENCE THE PAST SEVERAL DAYS AND TO AND
EXTENT MUCH OF THIS SUMMER OF HIGHS TENDING TO BE A DEGREE TO TWO OR
MORE COOLER THAN MOST GUIDANCE ALSO A REASON TO PASS TO NEXT FORECAST
CYCLE.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 228 PM CDT MON JUL 21 2014

FORECAST FOCUS ON ANOTHER PERIOD OF BELOW NORMAL TEMPERATURES. THE
12Z/21 ECMWF NOT AVAILABLE AS OF THIS WRITING.

TUESDAY NIGHT...COLD FRONT WILL MOVE THROUGH THE CWA BUT FORCING IS
WEAK AND CAP IS STILL RATHER STRONG SO WILL ONLY CARRY A CHANCE OF
THUNDERSTORMS ALONG THE FRONT.

WEDNESDAY THROUGH THURSDAY...WITH THE PASSAGE OF THE FRONT WE RETURN
TO A NORTHWEST FLOW ALOFT...AND SURFACE HIGH PRESSURE ACROSS THE
GREAT LAKES. THIS WILL RETURN THE COMFORTABLE TEMPERATURES AND
HUMIDITY THAT WE HAVE SEEN QUITE OFTEN THIS SUMMER. HIGHS WILL BE IN
THE 70S AND LOWS IN THE 50S.

FRIDAY THROUGH MONDAY...THE CWA WILL BE ON THE EDGE OF THE HEAT DOME
CENTERED IN THE SOUTHERN ROCKIES WITH MUCH COOLER READINGS WELL TO
OUR NORTHEAST WITH AN UPPER LOW PARKED OVER EASTERN CANADA. THIS WILL
PUT OUR AREA IN A NW/WNW FLOW WITH THE POTENTIAL FOR SEVERAL MCS
EVENTS IN OR NEAR THE CWA. FOR NOW WILL HAVE CHANCE POPS THIS PERIOD
BUT CONFIDENCE IS LOW IN REGARDS TO TIMING AND STRENGTH. HIGH
TEMPERATURES SHOULD BE MAINLY IN THE UPPER 70S TO LOWER 80S WITH
LOWS IN THE 60S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1121 PM CDT MON JUL 21 2014

THE CHANCE FOR STORMS OVERNIGHT IS VERY VERY LOW...SO...WILL
CONTINUE VFR AND DRY FORECAST THROUGH TUESDAY AFTERNOON...AND
EVENING. A WARM LAYER OF AIR ALOFT WILL CAP OFF ANY
THUNDERSTORMS...RESULTING IN HOT AND HUMID CONDITIONS AT LOW
LEVELS...BUT FEW IF ANY STORMS. I HAVE SWITCHED WINDS TO NORTHWEST
TUESDAY EVENING...AS A COLD FRONT MOVES THROUGH...ALSO WITH LITTLE
IF ANY STORMS.
ERVIN

&&

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

$$

SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...HAASE
AVIATION...ERVIN





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