Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KDVN 240417
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1117 PM CDT SAT AUG 23 2014

.SYNOPSIS...
ISSUED AT 334 PM CDT SAT AUG 23 2014

LINEAR MCS WELL EAST OF CWA INTO NORTHWEST INDIANA AS OF 3 PM CDT.
THIS STORM COMPLEX WAS RESPONSIBLE FOR THE WIDESPREAD AND MUCH
NEEDED RAIN THIS AM... WITH AMOUNTS MOSTLY OF 0.50 TO 1.5 INCHES
WITH LOCALLY 2-3+ INCHES. LINGERING DEBRIS CLOUDS AND EASTERLY
WINDS IN WAKE OF MCS HOLDING TEMPS DOWN INTO THE 70S WITH LOWER
TO MID 80S FAR WEST AND SOUTHERN CWA WHERE MORE THINNING OF CLOUDS
HAS OCCURRED. SFC PATTERN FEATURES PAIR OF FRONTS WITH ONE TO THE
NORTH EXTENDING FROM LOW OVER SOUTH DAKOTA EASTWARD INTO WISCONSIN.
SECONDARY BOUNDARY ENHANCED BY OUTFLOW /RAIN COOLED AIR/ APPEARS
TO EXTEND FROM NEBRASKA THROUGH NORTHEAST MISSOURI AND SOUTH
CENTRAL ILLINOIS. UPPER LEVEL PATTERN FEATURES AMPLIFIED RIDGE
OVER MID MISSISSIPPI VLY WITH STRONG SHORTWAVE TROUGH OVER THE
NORTHERN ROCKIES.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 334 PM CDT SAT AUG 23 2014

OUTFLOW/RAIN COOLED AIR ENHANCED BOUNDARY TO OUR SOUTH EXPECTED TO
LIFT NORTH TONIGHT AND SUNDAY AS LOW PRESSURE LIFTS THROUGH THE
NORTHERN PLAINS AHEAD OF SHORTWAVE TROUGH. KEPT POPS BELOW MENTION
TONIGHT WITH LACK OF TRIGGER IN WATER VAPOR AND GENERAL SUBSIDENCE
IN WAKE OF MCS... BUT SOME INDICATION OF WEAK ELEVATED THETA-E
ADVECTION AND CONVERGENCE WITH WEAKER BRANCH OF LOW LEVEL JET
LATE THIS EVE INTO OVRNGT OVER FAR EAST AND ESPECIALLY EAST OF CWA
THAT MAY NEED TO BE WATCHED FOR SOME ISOLD DEVELOPMENT. OTHERWISE...
CONTINUED MUGGY WITH LOWS MAINLY IN THE LOWER 70S WITH SOME UPPER 60S
POSSIBLE NORTH/EAST AND MID 70S POSSIBLE IN SPOTS FAR SOUTH. POTENTIAL
FOR SOME FOG TO DEVELOP LATE THIS EVE/OVRNGT AHEAD OF THE
BOUNDARY...MAINLY NEAR AND NORTH OF I-80 AND HAVE INCLUDED AS IF
DEVELOPS COULD SEE AREAS OF DENSE FOG GIVEN ABUNDANT LOW LEVEL
MOISTURE AIDED BY THIS AM RAIN.

SUNDAY... BOUNDARY TO ESSENTIALLY WASH OUT OR MIX NORTHWARD IN
STRENGTHENING LOW LEVEL SOUTHERLY GRADIENT. THIS WILL USHER IN
WARM ELEVATED MIXED LAYER OR CAP AND WITH LACK OF TRIGGER OR FOCUSING
MECHANISM SHOULD PRECLUDE ANY CONVECTION. IT WILL ALSO MEAN MUCH
WARMER TEMPS THAN THOSE OF TDY GIVEN ABSENCE OF CONVECTION. ANY
RESIDUAL AM FOG AND LOW CLOUDS SHOULD QUICKLY ERODE BY MID TO LATE
AM WITH MIXING TAPPING DRIER AIR ALOFT. 850 MB TEMPS OF 20-23C
SUPPORTIVE OF WIDESPREAD HIGHS IN THE UPPER 80S AND LOWER 90S.
THIS COUPLED WITH DEWPTS AROUND 70 OR IN THE 70S WILL YIELD HEAT
INDICES IN THE RANGE OF 95 TO AROUND 100 DEGS FOR THE AFTERNOON AND
THUS A HEAT ADVISORY MAY BE NEEDED. SOME UNCERTAINTY THOUGH WITH
MODEL SOUNDINGS MIXING TO NEAR 850 MB AND PULLING DOWN DRIER AIR
THAT COULD SEE DEWPTS ACTUALLY A BIT LOWER AND MORE IN THE 60S
(MAINLY MID TO UPPER 60S) ESPECIALLY WEST OF THE MISSISSIPPI RVR IN
STRONGER GRADIENT AS OCCURRING IN PARTS OF EASTERN KANSAS AND WESTERN
MISSOURI... BUT THESE AREAS ALSO GUSTING TO AROUND 20 KTS OR SO AND
DRY. SO THE BATTLE BETWEEN MIXING AND RECENT WET GROUND ALONG WITH
EVAPOTRANSPIRATION FROM CROPS WILL BE ONE TO WATCH AND MAKES DEWPTS
CHALLENGING AND SUBSEQUENT TEMPS AND HEAT INDICES FORECAST CHALLENGING.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 307 PM CDT SAT AUG 23 2014

MAIN CONCERNS IN THE EXTENDED FORECAST ARE INITIALLY THE HEAT AND
HUMIDITY IN STORE FOR MONDAY AND TUESDAY...FOLLOWED BY MUCH COOLER
TEMPS FOR THE SECOND HALF OF NEXT WEEK.  HEAT ADVISORY CRITERIA OF
HEAT INDICES OF 100-105 DEGREES LOOKS TO BE A GOOD BET FOR AREAS
ALONG AND SOUTH OF INTERSTATE 80 BOTH MON PM AND TUE PM. ACTUAL
HIGHS WILL MAINLY BE IN THE UPPER 80S TO MID 90S BOTH DAYS.  A COLD
FRONT WILL APPROACH THE AREA SUNDAY NIGHT...FINALLY MOVING THROUGH
THE AREA BY THU. WITH FRONTAL BOUNDARY IN THE VICINITY...RAINFALL
CHANCES ARE PRETTY GOOD...ESPECIALLY FOR AREAS NORTH OF I 80.  LATE
TUE THROUGH WED NIGHT APPEARS TO HAVE THE BEST CHANCES AT
RAINFALL... WITH HIGH CHANCE TO LIKELY POPS IN THAT PERIOD. WED WILL
BE THE TEMP TRANSITION DAY...WITH HIGHS IN UPPER 70S NW...TO UPPER
80S SE.  THU...AND MORE SO FRI...MUCH COOLER AND LESS HUMID
CONDITIONS WILL BE FELT...WITH HIGHS IN THE MID 70S TO LOW 80S...AND
THAT MIGHT BE ON THE WARM SIDE. LINGERING LOW/SLIGHT CHANCE POPS
REMAIN FOR LATE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1116 PM CDT SAT AUG 23 2014

A WARM FRONT WILL LIFT NORTH THROUGH EASTERN IOWA AND NORTHERN
ILLINOIS THROUGH EARLY SUNDAY. THIS SHOULD END THE THREAT FOR
THUNDERSTORMS FOR ABOUT 24 HOURS...SO THIS SET OF TAFS IS HIGH
CONFIDENCE DRY. WE WILL SEE FOG AND SOME LOWER CIGS OF 1200 FT
THIS EVENING AND OVERNIGHT NORTH OF THE WARM FRONT. THUS...PERIODS
OF MVFR TO IFR VISIBILITIES IN FOG AND LOWER CIGS WILL BE POSSIBLE
AT ALL SITES THROUGH SUNRISE. SUNDAY WILL SEE SOUTH WINDS INCREASE
AND WIDESPREAD VFR WEATHER...THOUGH CONDITIONS WILL ALSO BE VERY
HOT AND HUMID. ERVIN

&&

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

$$

SYNOPSIS...05
SHORT TERM...05
LONG TERM...14
AVIATION...ERVIN






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.