Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 280539
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1139 PM CST SAT DEC 27 2014

.SYNOPSIS...
ISSUED AT 219 PM CST SAT DEC 27 2014

COLDER AIR MOVING INTO THE MIDWEST WITH CLEARING SKIES TO PASS ACROSS
THE FORECAST AREA THE NEXT 6 TO 8 HOURS FROM SUBSIDENCE AND DRIER AIR.
TEMPERATURES SLOWLY FALLING INTO THE LOWER 30S AT 2 PM...OR CLOSER TO
NORMAL FOR LATE DECEMBER ON NW WINDS OF 15 TO 25 MPH. SURFACE AND UPPER
AIR ANALYSIS SHOWS NEAR NORMAL TEMPERATURES AND DRY THE NEXT FEW DAYS
WITH STRONGER...COLDER ARCTIC HIGH PRESSURE TO ARRIVE BY TUESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 219 PM CST SAT DEC 27 2014

SHORT TERM FORECAST CONFIDENCE ASSESSMENT...GOOD OR ABOVE AVERAGE WITH
MAIN ISSUE CLEARING THIS EVENING. TRENDS SUGGEST CLEARING AROUND DUSK
FAR WEST TO MID TO LATE EVENING EAST OF THE MISSISSIPPI RIVER. LOW
DEWPOINTS SUGGEST MINS AT OR BELOW THE COLDEST GUIDANCE TONIGHT FOR
LATER SHIFTS TO MONITOR TRIMMING BY LATE EVENING IF DEWPOINTS FALL
BELOW FORECAST GUIDANCE.

TONIGHT...CLEARING FROM WEST TO EAST SHOULD OCCUR BETWEEN 6 PM WEST
TO 10 TO 11 PM EAST WITH WESTERLY WINDS DIMINISHING TO 5 TO 10 KTS.
FAIR SKIES AND WINDS DECREASING TO AROUND 5 KTS BY MORNING WITH MODERATE
BL DECOUPLING TO HAVE MINS UPPER TEENS FAR NW TO LOWER 20S SE SECTIONS.

SUNDAY...SUNNY TO MOSTLY SUNNY SKIES WITH A FEW HIGH CLOUDS POSSIBLE...LIGHT
WESTERLY WINDS 5 TO AROUND 10 MPH AND HIGHS 32 TO 37 DEGREES OR SLIGHTLY
ABOVE NORMAL...NOT TOO BAD FOR LATE DECEMBER FOR ANY OUTSIDE ACTIVITY
LIKE REMOVING LIGHTS OR DECORATIONS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 219 PM CST SAT DEC 27 2014

MONDAY...NNE FLOW AND CAA WILL BRING IN DRIER AIR. 850 TEMPS WILL
FALL FROM -6 C MONDAY MORNING TO AROUND -14 C BY TUESDAY MORNING.
DUE TO LACK OF SNOW COVER...SFC TEMPS WILL STILL BE NEAR AVG IN
UPPER 20S TO MID 30S. SLIGHT CHANCE FOR SOME SNOW SHOWERS/FLURRIES
BUT NOTHING ORGANIZED. 925 MB FRONTOGENESIS REMAINS TO THE WEST OVER
CENTRAL/WESTERN IOWA AND VORT. MAX PASSES TO THE SOUTH ACROSS MO.

TUESDAY AND WEDNESDAY...TREND TO BELOW NORMAL TEMPS ARE FORECAST
DURING THIS TIME. 1000-500 MB THICKNESS WILL BE LOWEST...NEAR
510-516 DAM...ON TUESDAY BEFORE INCREASING ON WEDNESDAY. BOTH THE
GFS/ECMWF DROP 850 TEMPS TO BETWEEN -12 C TO -14 C ON TUESDAY WITH
SOME MODERATION BY WEDNESDAY. NW FLOW AT THE SFC WILL BACK TO SW
FLOW BY WEDNESDAY AS A STRONG 1045-1050 MB SFC HIGH WORKS ITS WAY
SOUTHWARD DOWN THE IMMEDIATE FRONT RANGE/WESTERN PLAINS. THE
CONSENSUS TEMP BLENDS HAVE NOW TRENDED TOWARD THE RAW GFS/ECMWF
OUTPUT SO DID NOT MAKE ANY NOTABLE CHANGES TO TEMP FORECAST.

THURSDAY...WARMER BUT STILL NEAR TO SLIGHTLY BELOW NORMAL TEMPS IN
THE LOWER 20S TO NEAR 30 F AND CONTINUED DRY CONDITIONS.

FRIDAY AND SATURDAY...MODEL DISCREPANCIES ARE QUITE LARGE. AT THE
162 HR FORECAST VALID 06Z/SAT (1/3/2014) THE GFS HAS AN ORGANIZED
CLOSED-OFF MID-LEVEL LOW CENTERED JUST NORTH OF ST. LOUIS AND THE
DGEX AND GEM FAVOR A MORE NORTHERN TRACK SIMILAR TO THE GFS.

THE ECMWF HAS THIS SAME FEATURE WAY BACK TO THE SOUTHWEST OVER
SOUTH-CENTRAL OKLAHOMA/NORTH-CENTRAL TEXAS. THIS SOLUTION WOULD KEEP
ANY APPRECIABLE MOISTURE WELL TO OUR SE ACROSS THE OHIO VALLEY.
CONVERSELY...IF THE 12.27/12Z RUN OF THE GFS WERE TO VERIFY IT WOULD
BE OUR FIRST WIDESPREAD ACCUMULATING SNOWFALL SINCE THE END OF
NOVEMBER. ALTHOUGH PTYPE COULD ALSO BE AN ISSUE THROUGH THE EVENT
WITH THE GFS PUSHING 850 MB TEMPS TO NEAR 0 C UP TO THE QUAD CITIES.

THIS SYSTEM DOES NOT APPEAR TO HAVE THE UPPER SUPPORT TO BE VERY
STRONG BUT IT WILL HAVE PLENTY OF MOISTURE AVAILABLE WITH NO
ORGANIZED AREA OF LOW PRESSURE LOCATED TO ITS SOUTH. THE QUESTION IS
WHEN DOES THE MID-LEVEL LOW...INITIALLY OVER THE FOUR CORNERS EARLY
NEXT WEEK...PHASE WITH THE POLAR BRANCH OF THE JET THAT WILL BE
PUSHING INTO THE CENTRAL PLAINS/MIDWEST. KEPT 30 PERCENT POPS FOR
FRIDAY INTO EARLY SATURDAY MORNING AS MANY DETAILS NEED TO BE WORKED
OUT. STAY TUNED TO THE LATEST FORECAST INTO NEXT WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1131 PM CST SAT DEC 27 2014

A RIDGE OF HIGH PRESSURE WILL MOVE SLOWLY SOUTHEAST THROUGH THE
REGION THE REST OF TONIGHT AND SUNDAY. MVFR CIGS HAVE CLEARED MOST
OF THE AREA...BUT ARE STILL LINGERING OVER SOUTHEAST IOWA AND
NEARBY SECTIONS OF WESTERN IL AND NORTHEAST MO. CURRENT TIMING
SUGGEST THE CLEARING SHOULD REACH THE MISSISSIPPI RIVER AROUND 08Z
OR 09Z. OTHERWISE VFR CONDITIONS WILL PREVAIL OVER THE REGION
THROUGH SUNDAY AFTERNOON. A WEAK COLD FRONT DROPPING SOUTH THROUGH
THE REGION WILL BRING A RISK OF MVFR CIGS MOVING BACK IN FROM THE
NORTH LATE SUNDAY EVENING. THE TIMING OF THE ARRIVAL OF THE LOWER
CLOUDS IS QUESIONABLE BUT THEY COULD REACH KDBQ AND KCID JUST BEFORE
06Z.

&&

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

$$

SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...UTTECH
AVIATION...DLF






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