Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 281748
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1248 PM CDT THU MAY 28 2015

.UPDATE...
ISSUED AT 1016 AM CDT THU MAY 28 2015

A BAND OF CONVECTION IS RUNNING FROM NORTH OF KFNB TO KMHL IN
MISSOURI. THE THUNDERSTORMS ARE CONFINED TO THE SOUTHERN END OF
THE BAND WITH MORE RAIN ACROSS THE REST OF THE BAND.

IF TRENDS FROM THE RAP ARE CORRECT...THE BAND OF PRECIPITATION
WILL RUN INTO SLIGHTLY DRIER AIR AND DECREASING FORCING THROUGH
MID DAY. AS SUCH THE CURRENT BAND SHOULD SEE SOME DECAY TO IT AND
BEGIN ARRIVING IN THE FAR SOUTHWEST/SOUTH PRIOR TO MID AFTERNOON.

UPDATE ISSUED AT 643 AM CDT THU MAY 28 2015

HAVE EXPANDED PCPN CHCS A BIT MORE ACROSS THE SOUTHWEST AND
BROUGHT THEM IN A BIT EARLIER AS LATEST SEVERAL RUNS OF
HRRR CONSISTENT IN BRINGING SOME SHOWERS INTO SOUTHWEST CWA
TOWARD MID PM THROUGH LATE PM... AND MAY BE LATCHING ONTO
MCV WHICH IS SUGGESTED IN REGIONAL RADAR LOOP. UPDATED GRIDS/
ZFP OUT SOON.

&&

.SYNOPSIS...
ISSUED AT 320 AM CDT THU MAY 28 2015

HIGH PRESSURE IN FIRM CONTROL EARLY THIS AM BUT BEGINNING TO SHIFT
EAST TOWARD THE OHIO VLY WITH LIGHT SOUTHERLY RETURN FLOW
DEVELOPING. ACTIVE CONVECTION /SEVERAL LINEAR CLUSTERS/ FOUND
ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS EARLY THIS AM
IN VICINITY OF STATIONARY FRONTAL ZONE AND WITHIN PLUME OF
DEEPER MOISTURE AIDED BY SEVERAL MESOSCALE CONVECTIVE VORTICES.
OVER NEXT 24 HRS THE FLOW ALOFT WILL BECOME SOUTHWESTERLY AND WILL
SHUTTLE THESE DISTURBANCES NORTHEASTWARD BRINGING RAIN CHANCES
BACK TO THE AREA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT THU MAY 28 2015

TODAY... HIGH PRESSURE WILL REMAIN THE DOMINANT FEATURE WHILE
SHIFTING INTO THE OHIO VALLEY. SURFACE WINDS WILL BACK TO
SOUTHEAST AND INCREASE TO AROUND 10 TO 15+ MPH AND CONTINUE TO
DRAW IN DRIER AIR THUS CHEWING AWAY OR ERODING ANY PCPN
INITIALLY THIS AFTN...WITH JUST SLIGHT CHC OF A SHOWER OR WEAK
STORM FAR SW CWA LATE PM AHEAD OF INITIAL SHORTWAVE. OVERALL
JUST PARTLY TO MOSTLY SUNNY WITH MAINLY HIGH CLOUDS.
SOUTHEASTERLY WIND DIRECTION NOT FAVORABLE FOR MUCH WARMUP AND
PROGGED LOW LEVEL THICKNESS AND VERIFICATION OF HIGHS FROM YSTDY
ALONG WITH TRAJECTORY METHOD ALL SUPPORTIVE OF HIGHS IN RANGE
FROM 79-84 AND WITH COMFORTABLE HUMIDITY LEVELS SHOULD MAKE
FOR ANOTHER VERY FINE LATE SPRING DAY.

TONIGHT... SOUTHWEST FLOW AND SEVERAL SHORTWAVES WILL RESULT IN
DEVELOPING RAIN CHANCES. SOUTHEASTERLY FLOW THROUGH 850 MB
STILL USHERING IN DRIER AIR FROM DEPARTING HIGH AND THUS LIMITING
MOISTURE AXIS AND SUBSEQUENT BETTER PCPN CHCS TO WESTERN CWA...
ALTHOUGH SMALL PCPN CHCS EXIST EASTERN CWA LATE EVE/OVERNIGHT
WITH POTENTIAL WARM ADVECTION WING WITH VEERING LOW LEVEL JET
AHEAD OF MORE WIDESPREAD ACTIVITY LIFTING THROUGH CENTRAL IA. LOWS
GENERALLY IN RANGE FROM 59 TO 64.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 320 AM CDT THU MAY 28 2015

MAIN FORECAST CONCERN FOR THE LONG TERM ARE THE CHANCES FOR RAIN
AND THUNDER AT THE BEGINNING OF THE PERIOD. LITTLE CHANGE FROM
TODAYS FORECAST AND LAST NIGHTS FORECAST IS EXPECTED. AFTER THIS
SYSTEM MOVES THROUGH...WE SEE A QUITE REST OF THE EXTENDED
FORECAST.

FRIDAY AFTERNOON WE SHOULD BE SITTING IN THE DEEP MOISTURE.  THE
LARGE...ILL DEFINED H5 WAVE WILL BE MOVING INTO THE AREA.  LIKE THE
DAY SHIFT NOTED...THERE IS A LACK OF STRONG SHRTWV WITH THIS SYSTEM.
CURRENT FEELING IS THAT CONVECTION WILL BECOME MORE NUMEROUS IN THE
AFTERNOON AS THE FRONT APPROACHES THE AREA.  INSOLATION WILL HELP TO
BUILD A HEALTHY AMOUNT OF CAPE FOR THUNDERSTORMS AND POSSIBLY STRONG
UPDRAFTS.  WITH THE WEAK SHRTWV THERE IS A LACK OF SHEAR...IN FACT
DEEP LAYER IS SHEAR IS 20 KNOTS OR LESS.  CONVECTION ON FRIDAY WILL
BE DICTATED BY COLD POOLS AND BE MULTICELL OR SINGLE CELL IN NATURE.
THEREFORE THUNDERSTORMS WILL NOT LAST LONG AND THE THREAT FOR SEVERE
WEATHER WILL BE VERY LOW. THE FLOW...AND RESIDUAL MOISTURE IN THE
AREA WILL LEAD TO HIGH PWATS.  WITH THE THUNDERSTORMS AND HIGH
PWATS....LOCALIZED MINOR FLOODING COULD OCCUR. THE FRONT SHOULD MOVE
THROUGH THE AREA ON SATURDAY DAY AND WILL LEAD TO A DRY SATURDAY
EVENING.

COOLER AND DRIER AIR ARE STILL ON TAP FOR SATURDAY NIGHT AND SUNDAY.
AFTER THIS THE FLOW BECOMES MORE ZONAL...THIS WILL LEAD TO A GRADUAL
WARM UP ACROSS THE AREA.  MIDWEEK WE COULD SEE RETURN MOISTURE AND
POSSIBLY AND ACTIVE WEATHER PATTERN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1245 PM CDT THU MAY 28 2015

VFR CONDITIONS WILL BE SEEN THROUGH 00Z/29 WITH HIGH AND THEN MID
LEVEL CLOUDS INCREASING ACROSS THE AREA. AFT 00Z/29 VFR CONDITIONS
ARE EXPECTED TO CONTINUE WITH ISOLATED TO SCATTERED SHRA AND
POSSIBLY A TSRA. KCID/KDBQ HAVE SLIGHTLY BETTER CHANCES OF SEEING
A PERIOD OF MVFR CONDITIONS WITH A POTENTIAL TSRA FROM 06Z/29 THROUGH
SUNRISE FRIDAY.

&&

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

$$

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


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