Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 270331
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1031 PM CDT SAT JUL 26 2014

.UPDATE...
ISSUED AT 959 PM CDT SAT JUL 26 2014

LATE EVENING UPDATE TO ADD FOG TO FORECAST GRIDS. THE LOWEST
VISIBILITIES HAVE BEEN ACROSS THE FAR SOUTH...ALONG THE SWATH THAT
RECEIVED RAIN EARLIER TODAY. HAVE MAINTAINED SLIGHT CHANCE POPS
OVERNIGHT WITH FRONT YET TO PUSH THROUGH THE FORECAST AREA. NOT
OUT OF THE QUESTION TO GET A FEW STRONG TO NEAR SEVERE
STORMS...BUT OVERALL THREAT IS LOW.

&&

.SYNOPSIS...
ISSUED AT 314 PM CDT SAT JUL 26 2014

12Z UA ANALYSIS HAS A LLJ RUNNING FROM THE WESTERN PLAINS INTO THE
LOWER MISSOURI VALLEY. A POOL OF DEEP MOISTURE WAS ACROSS EASTERN
IOWA AND ILLINOIS WITH A SECONDARY FEED OF DEEP MOISTURE FROM THE
BIG BEND IN TEXAS INTO THE CENTRAL PLAINS. SATELLITE/RADAR TRENDS
THROUGH MID AFTERNOON SHOW PLENTY OF LOW CLOUDS ACROSS THE AREA WITH
NEW CONVECTION FROM NORTHERN MISSOURI INTO WESTERN ILLINOIS.

18Z SFC ANALYSIS HAS SEVERAL WEAK LOWS FROM NEAR KFSD INTO NORTHERN
KANSAS. A FRONTAL BOUNDARY RAN FROM A LOW NEAR KCNK ACROSS NORTHERN
MISSOURI AND INTO CENTRAL ILLINOIS. A COLD POOL FROM A DECAYING
THUNDERSTORM COMPLEX WAS ACROSS NORTHWEST IOWA. SEVERAL OTHER WEAK
BOUNDARIES WERE ACROSS CENTRAL IOWA AND NORTHERN ILLINOIS. DEW
POINTS WERE IN THE 60S ACROSS THE MIDWEST WITH 70 DEW POINTS FROM
THE GULF COAST INTO THE MID MISSISSIPPI VALLEY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 314 PM CDT SAT JUL 26 2014

THE EVOLUTION OF CONVECTION THIS AFTERNOON IS IN QUESTION. THE LOW
CLOUDS HAVE PERSISTED LONGER THAN THOUGHT...AND...NEW DEVELOPMENT
HAS OCCURRED DURING THE DAY. SAID CLOUDS HAVE SUPPRESSED
TEMPERATURES AND LIMITED THE AMOUNT OF HEATING.

12Z AND 18Z SOUNDINGS CONTINUE TO SHOW PLENTY OF WARM AIR ALOFT
WHICH IS HELPING TO SUPPRESS CONVECTION. THE EXCEPTION IS ALONG THE
BOUNDARY FROM NORTHERN MISSOURI INTO WESTERN ILLINOIS. DIFFERENTIAL
HEATING SOUTH OF THE BOUNDARY COMBINED WITH A DISTURBANCE ALOFT HAS
ALLOWED CONVECTION TO DEVELOP THERE.

THROUGH LATE AFTERNOON LIMITED IF ANY CONVECTION IS EXPECTED ACROSS
THE NORTHERN HALF OF THE AREA. THE SOUTH THIRD OF THE AREA WILL SEE
CONVECTION PERSIST WITH SOME DEVELOPMENT POSSIBLE UP TO I-80.

THIS EVENING ISOLATED CONVECTION MAY BE POSSIBLE ACROSS THE NORTHERN
HALF OF THE AREA AS A WEAK DISTURBANCE MOVE THROUGH. IF FORCING CAN
INCREASE THE CONVECTION ACROSS THE SOUTH HALF MAY GROW UPSCALE INTO
A THUNDERSTORM COMPLEX THAT MOVES INTO CENTRAL AND EASTERN ILLINOIS
BY LATE EVENING.

AFTER MIDNIGHT ANY LINGERING CONVECTION ACROSS THE AREA WILL SLOWLY
DISSIPATE AS THE MAIN COLD FRONT MOVES THROUGH THE REGION.

DRY CONDITIONS WILL BE SEEN ACROSS THE AREA SUNDAY MORNING. BREEZY
CONDITIONS WILL DEVELOP DURING THE MID TO LATE MORNING HOURS AS
WINDS INCREASE.

SUNDAY AFTERNOON A WEAK DISTURBANCE WILL MOVE SOUTHEAST FROM
MINNESOTA INTO NORTHEAST ILLINOIS. MOISTURE IS LIMITED BUT THE COLD
AIR ALOFT AND FORCING SHOULD BE SUFFICIENT TO ALLOW SHOWERS AND A
FEW THUNDERSTORMS TO DEVELOP.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 314 PM CDT SAT JUL 26 2014

MONDAY NIGHT THROUGH THURSDAY...MEDIUM RANGE MODELS ARE IN GOOD
AGREEMENT WITH DEVELOPING A HIGH AMPLITUDE RIDGE OVER THE WESTERN US
WITH A DEEP TROUGH OVER THE EASTERN PART OF THE COUNTRY. THIS UPPER
AIR PATTERN WILL PRODUCE A NORTHWEST FLOW ALOFT AND BUILD SURFACE
HIGH PRESSURE OVER THE UPPER MISSISSIPPI VALLEY. ON MONDAY EVENING
WINDS WILL BE FROM THE NORTHWEST AND GUSTY AS HIGH PRESSURE MOVES
INTO REGION. PLEASANT CONDITIONS WILL FOLLOW NEXT WEEK WITH LOW
HUMIDITY AND BELOW NORMAL TEMPERATURES. HIGHS WILL BE IN THE UPPER
70S TO AROUND 80 WITH OVERNIGHT LOWS IN THE UPPER 50S AND LOWER 60S..

FRIDAY AND SATURDAY...LONG RANGE MODELS INDICATE THERE COULD BE
SHOWERS OR THUNDERSTORMS LATE NEXT WEEK AS A UPPER LEVEL SHORTWAVE
MOVES THROUGH THE NORTHWEST FLOW ALOFT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 959 PM CDT SAT JUL 26 2014

EVENING UPDATES TO TAFS TO ADD FOG AT ALL SITES. NORTHWEST WINDS
SHOULD HELP MIX OUT THE FOG LATE. LOWEST VSBYS AND PERIODS OF IFR
CIGS WILL BE AT KBRL.

&&

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

$$

UPDATE...RP KINNEY
SYNOPSIS...08
SHORT TERM...08
LONG TERM...KUHL
AVIATION...RP KINNEY





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