Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 260922
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
322 AM CST FRI DEC 26 2014

.SYNOPSIS...
ISSUED AT 320 AM CST FRI DEC 26 2014

06Z SFC ANALYSIS HAS A WEAK LOW NEAR KFOD WITH ANOTHER NEAR KGAG.
THE MAIN FRONTAL BOUNDARY RAN BETWEEN THESE TWO LOWS AND EXTENDED
NORTHEAST INTO LAKE SUPERIOR. DEW POINTS WERE IN THE 30S AHEAD OF
THE FRONT WITH SOME 40S ACROSS EASTERN TEXAS. DEW POINTS WERE IN THE
TEENS AND 20S ACROSS THE NORTHERN PLAINS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CST FRI DEC 26 2014

DRY AND WARM CONDITIONS WILL BE SEEN THROUGH SUNSET FRIDAY. ALTHOUGH
FORCING GRADUALLY INCREASES DURING THE DAY..IT WILL GO INTO
GENERATING AN INCREASE IN CLOUD COVER. TEMPERATURES WILL BE WELL
ABOVE NORMAL.

TONIGHT IS MORE INTERESTING. ALTHOUGH FAR FROM CLASSIC...WHAT IS
SUGGESTED BY THE MODELS IS THAT PRECIPITATION SHOULD OCCUR
ALONG/BEHIND THE FRONT. FORCING MAXIMIZES AROUND MIDNIGHT AND THEN
BEGINS TO DECREASE TOWARD MORNING.

THUS LIGHT RAIN WILL SLOWLY DEVELOP DURING THE EVENING AND GRADUALLY
SPREAD EAST OVERNIGHT. AFTER MIDNIGHT A RAIN/SNOW MIX SHOULD DEVELOP
WEST OF A GRINNELL IOWA TO LONE ROCK WISCONSIN LINE. IF FORCING IS
STRONG ENOUGH TO COOL THE ATMOSPHERIC COLUMN...THEN A CHANGE OVER TO
ALL SNOW MIGHT OCCUR WEST OF A GRINNELL TO MANCHESTER LINE PRIOR TO
SUNRISE. AT BEST...A DUSTING OF ACCUMULATION MAY OCCUR ON GRASSY
SURFACES.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 AM CST FRI DEC 26 2014

THE MAIN FORECAST ISSUES IN THE LONG TERM ARE LINGERING PRECIP TYPE
ISSUES WITH THE EXITING FRONT SATURDAY...FOLLOWED BY A COLDER SPELL.

26/00Z SYNOPTIC MODELS ARE IN REASONABLE AGREEMENT IN THE TIMING OF
THE SURFACE LOW/COLD FRONT EXIT AND THE TIMING OF THE COLDER AIR ON
SATURDAY. BUFKIT SOUNDINGS INDICATE SOME POTENTIAL FOR LIGHT SNOW TO
A RAIN/SNOW MIX...MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER
SATURDAY MORNING. THERE MAY BE SOME MINOR ADDITIONAL ACCUMULATIONS
ON GRASSY SURFACES IN THE NORTHWEST...BUT NOTHING OF SIGNIFICANCE IN
TERMS OF TRAVEL IMPACT. DEEP LAYER FORCING QUICKLY WANES AFTER
MIDDAY...AND WILL CARRY ONLY SLIGHT CHANCE POPS ACROSS THE EASTERN
FRINGE OF THE FORECAST AREA DURING THE AFTERNOON. A NORTHWEST WIND
GUSTING AROUND 25 MPH WILL KEEP TEMPS STEADY TO SLOWLY FALLING
DURING THE AFTERNOON...WITH MORNING HIGHS IN THE LOW 30S TO MID 40S
EXPECTED.

LOOKING AHEAD...EXPECT PROGRESSIVELY COLDER TEMPERATURES THROUGH
TUESDAY WITH BROAD UPPER TROUGHING ACROSS THE CENTRAL CONUS. EXPECT
A MAINLY DRY PERIOD...WITH THE POSSIBLE EXCEPTION OF MONDAY AS THE
GEM/ECMWF ARE ADVERTISING A WEAK WAVE THAT COULD BRING A BIT OF
LIGHT SNOW. THE MAIN HAZARD IN THE LONG TERM PERIOD WILL BE VERY
COLD WIND CHILL VALUES MONDAY NIGHT AND TUESDAY NIGHT. WIND CHILLS
OF 5 TO 15 BELOW ZERO ARE POSSIBLE TUESDAY NIGHT...QUITE A DEPARTURE
FROM THE RECENT MILD WEATHER. TUESDAY WILL LIKELY BE THE COLD
DAY...WITH HIGHS FORECAST IN THE TEENS TO LOWER 20S. A SLIGHT
REBOUND IN TEMPS IS POSSIBLE WEDNESDAY/THURSDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1136 PM CST THU DEC 25 2014

HAVE ADDED MENTION OF LOW LEVEL WIND SHEAR OVERNIGHT AND EARLY FRIDAY
MORNING. DVN WSR-88D SHOWING SSW WINDS 40-45 KTS 1-2KFT AGL ALSO
IN LINE WITH MODEL FCST SOUNDINGS AND EXPECT SFC WINDS TO REMAIN
SLIGHTLY BACKED SSE AROUND 10 KTS DURING THIS TIME WITH AN OCCASIONAL
GUST. OTHERWISE...VFR MID AND HIGH CLOUDINESS EXPECTED TO CONTINUE
THROUGH MUCH OF FRIDAY. LATER FRIDAY AFTERNOON AND FRIDAY NIGHT EXPECT
CONDITIONS TO DETERIORATE TO MVFR AND IFR WITH INCREASING LOW LEVEL
MOISTURE AHEAD OF A FRONTAL BOUNDARY SAGGING INTO THE AREA. MODELS
ESPECIALLY NAM AND GFS VERIFYING TOO MOIST WITH RETURN FLOW FROM
TX GULF COAST AND BASED ON THIS ALONG WITH OBS AND TRENDS HAVE OPTED
TO KEEP VFR CONDITIONS AT MLI AND BRL THROUGH FRIDAY EVENING... WHILE
ANTICIPATE LOWEST CONDITIONS DEVELOPING CID AND DBQ FRIDAY EVENING
NEAR THE SLOW MOVING FRONTAL ZONE. ANTICIPATE SOME LIGHT RAIN TO
DEVELOP FRIDAY EVENING ESPECIALLY MID TO LATE EVENING BUT UNCERTAIN
ON COVERAGE AND HAVE HANDLED WITH VCSH FOR NOW.

&&

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

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...RP KINNEY
AVIATION...05





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