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000
FXUS63 KDVN 091716
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1216 PM CDT SUN MAR 9 2014

.SYNOPSIS...
ISSUED AT 410 AM CDT SUN MAR 9 2014

HIGH PRESSURE RIDGE ADVANCING SOUTHEAST ACROSS THE CWA PROVIDING
CLEAR SKIES AND LIGHT WEST WINDS. AT 4 AM CDT TEMPERATURES RANGED
FROM 12 AT INDEPENDENCE TO 28 AT MACOMB. MID/HIGH CLOUDS WERE SPREADING
SOUTHEAST ACROSS THE NORTHERN PLAINS AS WARM AIR ADVECTION RETURNS
IN EARNEST.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT SUN MAR 9 2014

FORECAST FOCUS ON IMPRESSIVE WARM-UP BUT NEED TO KEEP AN EYE ON
THE HIGH POTENTIAL FOR BREAK-UP ICE JAMS ON AREA RIVERS AND STREAMS.

TODAY...OTHER THAN SOME THIN CIRRUS THERE WILL BE PLENTY OF
SUNSHINE. WITH THE HIGH PRESSURE RIDGE SLIPPING OFF TO OUR SOUTHEAST
THIS MORNING THE WINDS WILL BECOME SOUTHWEST. WITH LOW PRESSURE
PUSHING TOWARDS NORTH DAKOTA THE GRADIENT WILL TIGHTEN ESPECIALLY LATE
THIS MORNING AND AFTERNOON. 850 MB WINDS ARE PROGGED TO STRENGTHEN
TO 40 TO 50 KNOTS ACROSS THE CWA SO THIS SHOULD MIX DOWN SOME SURFACE
GUSTS TO AROUND 30 MPH. IN THIS SCENARIO THE GUIDANCE NUMBERS ARE
BIASED TO THE COOL SIDE AND THUS WILL BOOST READINGS HIGHER...ESPECIALLY
CONSIDERING WE ARE MELTING MORE SNOW EVERY DAY. SEEMS REASONABLE
THEN TO FORECAST MAXIMUM TEMPERATURES RANGING FROM THE LOWER 40S
IN EXTREME NORTHWEST IL (DEEPER SNOW PACK) TO THE MID 50S IN OUR
FAR SOUTHERN COUNTIES (LITTLE IF ANY SNOW COVER). WITH THIS QUICK
WARM-UP THE THREAT FOR BREAK-UP ICE JAMS ON SOME AREA RIVERS AND
STREAMS WILL BEGIN TO INCREASE.

TONIGHT...A MILD NIGHT AS LOW PRESSURE TRACKS FROM NORTHERN ND TO
THE NORTHERN GREAT LAKES. THIS WILL KEEP A SOUTHWEST BREEZE GOING
ALONG WITH MID/HIGH LEVEL CLOUDS. TEMPERATURES ARE EXPECTED TO
REMAIN ABOVE FREEZING ALL NIGHT CONTINUING THE MELTING PROCESS.
WILL FORECAST LOWS IN THE MID TO UPPER 30S AND THE LAST TIME LOWS
WERE ABOVE FREEZING AT MOST LOCATIONS WAS BACK ON FEBRUARY 20.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 410 AM CDT SUN MAR 9 2014

MON-MON NGT... DRY AND WARMER YET WITH MUCH ABOVE NORMAL TEMPS!
WILL LIKELY HAVE SOME MID/HIGH CLOUDS TO CONTEND WITH BUT EVEN
MOIST ADIABATIC LAPSE RATE SUPPORTIVE OF FAIRLY WIDESPREAD 50S
FOR HIGHS WITH PROGGED LOW LEVEL THICKNESS AND VERIFICATION OF
HIGHS FROM YSTDY (SAT 8TH) SIMILAR IN SUPPORT WITH NEAR 50/L50S
NORTH... TO L60S SOUTH AS LOW LEVEL THERMAL RIDGE POSITIONED
FAVORABLY OVER REGION AHEAD OF WEAK BOUNDARY WHICH LOOKS TO PASS
MON PM/NGT. WEAK COOL ADVECTION AND INCREASING CLOUDS MON NGT
SUPPORT SIDING NEAR WARMER SIDE OF GUIDANCE FOR LOWS WITH
MANY AREAS STAYING ABOVE 32F.

TUE-WED... THIS PERIOD REMAINS THE PRIMARY WEATHER CHALLENGE AND
THE ONE FLY IN THE OINTMENT OF AN OTHERWISE FAIRLY DECENT FORECAST.
STILL LOWER CONFIDENCE AS MODERATE VARIANCES IN MODEL SOLUTIONS
CONTINUE PARTICULARLY WITH REGARD TO STRENGTH OF NEXT STORM SYSTEM
WITH SUBSTANTIAL IMPACTS TO PCPN AMOUNTS AND VERTICAL TEMP PROFILE
/PCPN TYPE/. OVERALL MODEL CONSENSUS SUGGESTS BAND OF POST-FRONTAL
PCPN SAGGING INTO THE NORTH 1/3-1/2 BY LATE TUE AM THROUGH TUE PM
ATTENDANT TO INCREASING MID LEVEL FRONTOGENETICAL FORCING IN RIGHT
LIFT QUADRANT OF GREAT LAKES JET. INITIALLY PCPN MAY FALL AS RAIN
GIVEN PRESENCE OF ELEVATED 925-850MB WARM NOSE BUT EVENTUALLY
STRENGTHENING COLD ADVECTION ON INCREASING N/NE WINDS SHOULD ERODE
WARM NOSE AND RESULT IN CHANGEOVER TO SNOW CONTINUING INTO TUE NGT
WITH FORCING WEAKENING AND FOCUS SHIFTING FURTHER SOUTH. SPEED AT
WHICH THE CHANGEOVER OCCURS AND TIMING OF WANING PCPN INTENSITY BOTH
CRITICAL IN PTYPE AND AMOUNTS... WITH BEST GUESS ATTIM OF AN INCH
OR TWO OF WET SNOW POSSIBLE HWY 30 NORTH BY TUE EVE.

AS MENTIONED THE FOCUS APPEARS TO THEN SHIFT TO OUR SOUTHERN CWA TUE
NGT INTO WED WHERE MOST MODELS HAVE REVERTED BACK TO A MORE PHASED
AND STRONGER SYSTEM WITH SURFACE LOW TRACKING TO OUR SOUTH FROM
CENTRAL/SOUTHERN MO INTO THE OHIO VLY BY WED... CLOSE ENOUGH TO
STILL SWIPE THE SOUTHERN CWA WITH MODERATE DEFORMATION ZONE AND
PCPN AMOUNTS. COULD INITIALLY SEE PCPN START AS RAIN ALBEIT BRIEFLY
AS STRENGTH OF COLD/DRY ADVECTION COUPLED WITH DYNAMICAL COOLING
SHOULD RESULT IN QUICK CHANGEOVER TO SNOW. TIMING OF CHANGEOVER AND
STRENGTH OF SYSTEM TO HAVE SUBSTANTIAL IMPACT ON AMOUNTS OF
RAIN/SNOW... WITH BEST GUESS ATTIM OF 1-4 INCH SNOWFALL ACCUMS
POSSIBLE SOUTHERN HALF OF CWA WITH HIGHER AMOUNTS FAVORING NEAR/S
OF HWY 34. THESE AMOUNTS OF COURSE SHOULD STRONGER MORE PHASED
SOLUTIONS PAN OUT... BUT MAIN ENERGY PACKETS STILL OFF WEST COAST AND
YET TO BE SAMPLED SO LIKELY TO SEE SOME VARIANCES IN MODELS FOR NEXT
24 HRS. THEREFORE... EXTREME CAUTION TOWARDS GETTING CAUGHT UP IN
ANY AMOUNTS ATTIM. CASE IN POINT NAM AND GEM MODELS REMAIN LESS PHASED
FOR US...A SOLUTION WHICH HAS BEEN SHOWN BY EVERY MODEL AT SOME POINT
PAST FEW DAYS. THIS WEAKER/LESS PHASED SCENARIO FOR US WOULD BE
SUPPORTIVE OF LIGHT POST-FRONTAL PCPN IN GRADUAL WEAKENING FRONTOGENESIS
BAND WITH ONLY LIGHT PCPN AMOUNTS AND MINOR SNOW ACCUMS IF ANY AT ALL.

WED-WED NGT... TEMPS TAKE A BRIEF HIT BUT STILL NOT TOO FAR OFF
NORMALS WITH HIGHS MAINLY IN THE 30S. GOING FCST HIGHS TOWARD
CONSENSUS BUT SHOULD WE SEE SOME ACCUMS THEN LIKELY WILL NEED TO
LOWER SEVERAL DEGS. HAVE UPPER TEENS AND 20S FOR LOWS WED NGT BUT
SIMILARLY MADE NEED LOWERING SOME WITH CLEARING SKIES AND HIGH
PRESSURE BUILDING IN.

THU-SAT... MODELS CONTINUE TO SUPPORT SUBSTANTIAL THERMAL MODERATION
BACK NEAR TO ABOVE NORMAL LATE WEEK AS SPLIT FLOW PATTERN REDEVELOPS
WITH STRONGER NORTHERN STREAM DOMINANT... WHICH WITH ENERGY PASSING
THROUGH GREAT LAKES WILL FAVOR THRUSTING AREA IN WARM SECTOR WITH
SOUTHERLY FLOW HENCE WARMING TEMPS WHILE STAYING MOSTLY DRY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1214 PM CDT SUN MAR 9 2014

BROAD SOUTHWEST FLOW WILL CONTINUE THE NEXT TWO DAYS...USHERING IN
MUCH MORE MILD AIR INTO THE REGION. VFR CONDITIONS ARE EXPECTED
THROUGHOUT THE PERIOD...WITH ANY CIGS ABOVE 15000 FT...AND
UNLIMITED VISIBILITY. SURFACE WINDS SHOULD BE 12 TO 25 KTS
SOUTHWEST...HIGH ENOUGH NOT TO INCLUDE MENTION OF LLWS ARE THE
INCREASE IN SPEEDS ALOFT SHOULD BE MORE GRADUAL...FROM THE SAME
DIRECTION...SOUTHWEST.

&&

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

$$

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