Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 270804
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
304 AM CDT WED MAY 27 2015

.SYNOPSIS...
ISSUED AT 300 AM CDT WED MAY 27 2015

WELL DEFINED SHORTWAVE IN WATER VAPOR IMAGERY PASSING THROUGH
CENTRAL IA ATTIM WITH VORT MAX ROUGHLY NEAR MARSHALLTOWN IA
MOVING EAST AT AROUND 25 KTS. SCATTERED SHOWERS WERE OCCURRING
AHEAD OF THIS FEATURE MOVING THROUGH NORTHEAST IA AND NORTHWEST IL
NORTH OF HWY 30. ALSO... A SMALL BATCH OF SHOWERS WAS ALSO
CLIPPING FAR SOUTHEAST CWA NEAR MACOMB IL ON NORTHERN FLANK OF
SECONDARY SHORTWAVE PASSING THROUGH CENTRAL MO. MOST IF NOT ALL
ACTIVITY IS EXPECTED TO BE EAST OF CWA BY SUNRISE... ALTHOUGH
MAY LINGER A BIT LONGER IN FAR NORTHEAST IL WITH VORT MAX PASSING
BY AROUND 13Z. WEAK COOL FRONT MOVING ACROSS NORTHWEST CWA ATTIM
ALTHOUGH LOSING ITS PUSH WITH POST FRONTAL PRESSURE RISES DECAYING.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT WED MAY 27 2015

A FEW SHOWERS MAY LINGER UNTIL 7-8 AM OVER FAR NORTHEAST CWA UNTIL THE
VORT MAX DEPARTS. THEN... WRAP-AROUND LOW CLOUDS MORE PREVALENT ACROSS
THE NORTHERN HALF OF CWA WILL PASS THIS AM FOLLOWED BY DECREASING
CLOUDINESS DURING THE AFTN WITH WEAK RIDGING AND SUBSIDENCE BUILDING IN.
TEMPS SEASONAL IN THE MID 70S TO AROUND 80 COMBINED WITH COMFORTABLE
HUMIDITY LEVELS SHOULD MAKE FOR A REAL NICE AFTN.

TONIGHT...MAINLY CLEAR SKIES AND COMFORTABLE TEMPS WITH WEAK SURFACE
HIGH PRESSURE IN CONTROL. OVERNIGHT THE HIGH PRESSURE RIDGE WILL SHIFT
EAST WITH LIGHT RETURN FLOW DEVELOPING. THIS WILL MAKE FOR A TRICKY
MIN TEMP FORECAST. IF WINDS STAY RELATIVELY LIGHT THEN POTENTIAL TO BE
NEAR COOL SIDE OF GUIDANCE WITH FAVORED DRAINAGE SITES IN THE MID 50S.
BANKING ON ENOUGH OF A LIGHT SOUTHERLY WIND OVERNIGHT TO SIDE NEAR BLEND
WITH LOWS MAINLY IN THE UPPER 50S TO AROUND 60.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 300 AM CDT WED MAY 27 2015

MAIN FORECAST CONCERN FOR THE LONG TERM ARE THE CHANCES FOR
PRECIPITATION THE END OF THIS WEEK.  THE CURRENT FORECAST HAS A
BEAUTIFUL WEEKEND IN STORE.  THE BEGINNING OF NEXT WEEK LOOKS DRY.
THIS BREAK IN ACTIVE WEATHER LOOKS TO EXTEND THROUGH THE LONG TERM
PERIOD WITH POSSIBLE ACTIVE WEATHER RETURNING MID WEEK NEXT WEEK.

H5 RIDGING WILL BE MOVING OUT OF THE AREA AT THE BEGINNING OF THE
LONG TERM.  SW FLOW WILL BE TRANSITIONING INTO THE AREA.  THIS WILL
HELP TO USHER MOISTURE BACK INTO THE AREA ALONG WITH INCREASING
CLOUD COVER.  MODELS SUGGESTS SOME SCHC OF POPS THURSDAY AFTERNOON.
HIRES WRF HAS SOME SHOWERS AND STORMS OVER THE AREA.  HOWEVER
BELIEVE THAT THE H5 RIDGING WILL HELP TO INHIBIT CONVECTION UNTIL
AFTER 00Z.  AFTER 00Z THE TROF APPROACHES THE AREA AND LEADS TO THE
DEVELOPMENT OF SHOWERS AND THUNDER OVERNIGHT.  ONCE AGAIN HIGH PWATS
RETURN TO THE AREA.  CAPE EXISTS FOR THUNDERSTORMS WITH POSSIBLY
HEAVY RAIN OVERNIGHT.  H85 MOISTURE TRANSPORT SUGGESTS THAT NW ZONES
OF THE CWA WILL HAVE THE BEST CHANCE FOR POPS OVERNIGHT INTO FRIDAY.

FRIDAY THE CHANCE FOR POPS INCREASES ACROSS THE WHOLE CWA.
INSOLATION SHOULD LEAD TO CAPE AOA 2000 J/KG ACROSS THE CWA WITH THE
GFS GOING EVEN HIGHER.  THINK THE GFS IS WELL OVERDONE WITH THE
INSTABILITY.  REGARDLESS THUNDERSTORMS WILL BE MORE NUMEROUS FRIDAY
INTO FRIDAY NIGHT.  LACK OF SHEAR WILL LIMIT ORGANIZED CONVECTION
AND SUBSEQUENT SEVERE THREAT.  DO THINK THAT STRONG STORMS WILL BE
POSSIBLE AND WOULD NOT BE SURPRISED TO GET A LARGE HAIL OR DAMAGING
WIND REPORT.   STORMS WILL LIKELY BE SINGLE CELL...SOME POSSIBLE
MULTICELL STORMS COULD OCCUR...THESE WILL LIKELY BE COLD POOL
DOMINATED.  SPC HAS US IN A DAY 3 MARGINAL RISK FOR WINDS AND HAIL.
THINK THAT HEAVY RAIN WILL LIKELY BE OUR MAIN THREAT ON FRIDAY.  H85
MOISTURE TRANSPORT VECTORS MOVE SOUTH THROUGH THE CWA DURING THE DAY
WITH SUFFICIENT CAPE.  PWATS ARE FORECAST TO BE 1.5 INCHES OR
SO...WHICH IS WELL INTO THE 90TH PERCENTILE.

AFTER THE FRONT MOVES THROUGH...CHILLY AIR MOVES IN.  1000-500
THICKNESS IS NEAR 540 ACROSS THE UP.  NEEDLESS TO SAY HEATERS MAY BE
NEEDED SATURDAY NIGHT/SUNDAY AM.  AFTER THIS...THE FLOW TURNS ZONAL
AND WE WARM TO MORE SEASONABLE TEMPS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1150 PM CDT TUE MAY 26 2015

MAINLY VFR CONDS THROUGH THIS TAF CYCLE EXCEPT MVFR CIGS/VIS BR
09-16Z/27. ISOLATED SHOWERS ARE EXPECTED OVERNIGHT. SOUTHWEST TO
WEST WINDS LESS THAN 10 KNOTS TONIGHT THEN AROUND 10 KNOTS ON
WEDNESDAY. SKIES WILL CLEAR DURING WEDNESDAY AFTERNOON AS SURFACE
HIGH PRESSURE PUSHES INTO THE AREA.

&&

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

$$

SYNOPSIS...05
SHORT TERM...05
LONG TERM...GIBBS
AVIATION...HAASE


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