Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 290430
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1130 PM CDT SUN SEP 28 2014

.SYNOPSIS...
ISSUED AT 307 PM CDT SUN SEP 28 2014

PERSISTENT UPPER LOW OVER MIDWEST FINALLY BEGINNING TO MOVE OUT WITH
SYSTEM OPENING UP /WEAKENING/ WHILE MOVING QUICKLY EASTWARD FROM
CENTRAL IA EARLY THIS AFTN BEING INFLUENCED BY SHORTWAVE TROUGH
AND STRENGTHENING WESTERLIES ADVANCING TOWARD THE US/CANADA BORDER.
AT THE SURFACE... HIGH PRESSURE CENTERED OVER THE CWA RESULTING IN
ANOTHER STELLAR AND COMFORTABLY WARM EARLY FALL DAY WITH NEAR CALM
WIND... ABUNDANT SUNSHINE AND DRY GROUND AIDING ABOVE NORMAL TEMPS IN
THE LOWER 80S MOST LOCATIONS AT 2 PM.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 307 PM CDT SUN SEP 28 2014

HIGH PRESSURE RIDGE TO DOMINATE TONIGHT WHILE SAGGING SLOWLY SOUTH
AHEAD OF UPPER LEVEL SHORTWAVE AND ATTENDANT SURFACE COLD FRONT
CONTINUING TO SHIFT ACROSS NORTHERN PORTIONS OF MN AND GREAT LAKES
THROUGH 12Z MON. DIURNALLY DRIVEN CUMULUS TO DISSIPATE WITH SUNSET
LEAVING MAINLY CLEAR SKIES TONIGHT... WHICH COUPLED WITH LIGHT
WIND AND DRY GROUND CONTINUES TO SUPPORT SIDING NEAR TO JUST BELOW
COOL SIDE OF GUIDANCE FOR LOWS... AND MAINLY IN RANGE OF 52-58F WITH
AGAIN SOME LOW LYING LOCATIONS POSSIBLY AROUND 50. MAY ALSO SEE SOME
PATCHY FOG TOWARD DAYBREAK IN RIVER VALLEYS AND LOW LYING AREAS WITH
SHALLOW... STEEP INVERSION.

MONDAY... THE COLD FRONT WILL MOVE THROUGH NORTHERN CWA DURING THE
AFTN AND IS PROGGED TO EXTEND NEAR THE HWY 30 CORRIDOR BY 00Z TUE.
NORMALLY WOULD GO ABOVE WARM SIDE OF GUIDANCE FOR HIGHS IN THIS
SCENARIO BUT BEING NEARLY OCTOBER AND SUN STRENGTH SIMILAR TO THAT
OF EARLY MARCH... ALONG WITH MIXING OF WESTERLY WINDS ALOFT
YIELDING WEST/NORTHWEST SURFACE COMPONENT TYPICALLY NOT FAVORABLE
FOR ABOVE GUIDANCE WARMING... AND ADDING IN SCT-BKN COVERAGE OF PM
CUMULUS ALL LEADS ME TO TEMPER EXPECTATIONS AND POSSIBLY ANTICIPATE
A VERY MINOR SETBACK ON HIGHS FROM PAST DAYS SOME LOCATIONS WITH GENERAL
RANGE FROM 77-83F. FORCING SUPPORTS ANY PCPN CHCS POST-FRONTAL AND
STAYING JUST NORTH OF CWA THROUGH 00Z ROOTED NEAR 850 MB AND ATTENDANT
MID LEVEL CONVERGENCE.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 307 PM CDT SUN SEP 28 2014

A WEAK FRONT WILL SLIDE DOWN LAKE MICHIGAN MONDAY NIGHT AND STALL
ACROSS THE AREA. FORECAST SOUNDINGS WOULD SUPPORT LOW LEVEL
CLOUDS...THAT ARE CURRENTLY BEHIND THE FRONT IN CANADA...ARRIVING IN
THE HIGHWAY 20 CORRIDOR AFTER MIDNIGHT. FORECAST SOUNDINGS WOULD
ALSO SUPPORT THE POTENTIAL FOR SOME DRIZZLE.

SUNRISE TUESDAY WILL STOP THE LOW LEVEL CLOUDS FROM GETTING MUCH
WEST OF A KIIB TO KVYS LINE. DAYTIME HEATING WILL ERODE THE CLOUDS
DURING THE MORNING LEAVING WARM AND DRY CONDITIONS THROUGH SUNSET.
ATTENTION THEN TURNS TO THE ARRIVING STORM SYSTEM.

TUESDAY EVENING WILL BE DRY ACROSS THE AREA AS THE BETTER MOISTURE
REMAINS IN THE WESTERN HALF OF IOWA. AFTER MIDNIGHT...MOISTURE AND
SOME FORCING START MOVING INTO THE FAR WEST BRINGING A THREAT OF
MAINLY SHOWERS. HOWEVER...A FEW RUMBLES OF THUNDER ARE POSSIBLE.

ON WEDNESDAY...THERE SHOULD BE A SLOW EASTWARD PROGRESS OF THE
PRECIPITATION ACROSS THE AREA. MOST AREAS EAST OF THE MISSISSIPPI
SHOULD REMAIN DRY DURING THE MORNING. DAYTIME HEATING AND THE
ARRIVAL OF THE NEXT UPPER LEVEL DISTURBANCE SHOULD INITIATE NEW
CONVECTION DURING THE AFTERNOON EAST OF THE MISSISSIPPI BUT THE
BETTER COVERAGE OF RAIN IS EXPECTED ACROSS THE WESTERN THIRD OF THE
AREA. WEDNESDAY WILL ALSO MARK THE LAST DAY OF ABOVE NORMAL
TEMPERATURES EAST OF THE MISSISSIPPI.

WEDNESDAY NIGHT ON...
WEDNESDAY NIGHT/THURSDAY THE MODEL CONSENSUS HAS HIGH CHANCE TO
LIKELY POPS FOR THE AREA. THE OVERALL BIG PICTURE OF DEEPER MOISTURE
ARRIVING ALONG WITH STRONGER FORCING WOULD SUPPORT CATEGORICAL POPS
LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.

THURSDAY NIGHT/FRIDAY THE MODEL CONSENSUS HAS CHANCE AND THEN SLIGHT
CHANCE TO CHANCE POPS RESPECTIVELY. THE COLD FRONT CLEARS THE AREA
THURSDAY NIGHT BUT ADDITIONAL DISTURBANCES MOVING IN THE FLOW ALOFT
SHOULD KEEP SHOWERS GOING. FRIDAY WILL BE BREEZY WITH TEMPERATURES
BELOW NORMAL FOR EARLY OCTOBER.

FRIDAY NIGHT THROUGH SUNDAY THE MODEL CONSENSUS HAS DRY BUT CHILLY
CONDITIONS ACROSS THE AREA WITH BELOW NORMAL TEMPERATURES. IF SKIES
CLEAR AND WINDS BECOME LIGHT BOTH FRIDAY AND SATURDAY NIGHTS...
FAVORED COLD AREAS ACROSS THE NORTHERN HALF OF THE AREA MAY SEE LOWS
IN THE UPPER 30S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1127 PM CDT SUN SEP 28 2014

HIGH PRESSURE WILL CONTINUE TO PROVIDE VFR CONDITIONS MOST OF THE
TAF CYCLE ALONG WITH LIGHT WINDS THROUGH LATE AFTERNOON MONDAY.
FOLLOWING THIS...A COLD FRONT WILL ARRIVE IN NORTHEAST IOWA...WITH
A WIND SWITCH TO NORTHEAST AROUND 6 TO 8 KTS FOR MONDAY EVENING.
OVERNIGHT TONIGHT...SHALLOW STEEP LOW LEVEL INVERSION WILL ONCE
AGAIN PROMOTE PATCHY FOG WITH MVFR TO LOCAL IFR VSBYS 09Z- 12Z
ESPECIALLY IN RIVER VALLEYS JUST LIKE THE PAST TWO EARLY MORNINGS
OVER THE WEEKEND. BEHIND THE COLD FRONT MONDAY EVENING...THERE
WILL BE SOME LOW CLOUD POTENTIAL MONDAY NIGHT...BUT WITH LOW
CERTAINTY...I HAVE ONLY INTRODUCED SCATTERED MVFR CLOUDS AT CID
AND DBQ.

&&

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

$$

SYNOPSIS...05
SHORT TERM...05
LONG TERM...08
AVIATION...ERVIN





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