Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 232036
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
336 PM CDT MON MAR 23 2015

.SYNOPSIS...
ISSUED AT 334 PM CDT MON MAR 23 2015

LATEST SFC ANALYSIS WAS INDICATING LOW PRESSURE WAVE ROLLING
EAST-SOUTHEASTWARD NEAR THE STL AREA ATTM...WHILE RIDGE AXIS WAS
ADJUSTING FROM THE SOUTHERN GRT LKS INTO THE CENTRAL PLAINS. COOL
EAST TO NORTHEAST LLVL FETCH NORTH OF THIS FEATURE ALONG WITH THE
CLOUDS...REALLY KEEPING A LID ON LOCAL TEMPS AND HINDERING MUCH OF
ANY KIND OF AFTERNOON WARM UP. ALOFT...WATER VAPOR IMAGERY WAS
INDICATING AN UPSTREAM LOBE OF RIDGING ACRS THE PLAINS HEADED THIS
WAY FRO TONIGHT...WHILE TOMORROW/TOMORROW NIGHTS WX MAKER L/W TROF
WAS LURKING ACRS THE WESTERN ROCKIES.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 334 PM CDT MON MAR 23 2015

TONIGHT...FIRST CONCERN IS IF ONGOING CLOUD COVER CAN MAINTAIN
OVERNIGHT WITH SEVERAL SHORT RANGE SOLUTIONS SUGGESTING SOME OF IT
BREAKING UP BOTH FROM THE SOUTHWEST...AND FROM THE DRY FETCH
NORTHEAST.  ALTHOUGH SOME BREAKS MAY OCCUR...WILL BANK ON MUCH OF
THE LOWER LEVEL CLOUDS GETTING NOCTURNALLY TRAPPED UNDER SUBSIDENCE
INVERSION AND KEEP THE CWA MOSTLY CLOUDY OVERNIGHT. BUT DO EXPECT TO
GET SOME TEMPORARY THINNING ENOUGH TO GET COOL OVERNIGHT LOWS DOWN
AT LEAST INTO THE UPPER 20S ESPECIALLY NORTH OF I80. MORE CLEARING
DURATION COULD LEAD TO SOME LOW TO MID 20S IN THE FAR NORTH/
NORTHEAST IN DRIER SFC AIR. THEN THE CHALLENGE TURNS TO THE INITIAL
WING OF ELEVATED WAA TYPE RAIN DEVELOPING ON NOSE OF VEERING TO THE
SOUTH/INCREASING H85 MB FLOW LATE TONIGHT. BULK OF THE 12Z RUN
SOLUTION SUGGEST BEST LOW TO MID LEVEL CONVERGENCE IN THIS
DEVELOPING WARM AND MORE MOIST CONVEYOR OCCURRING TO THE SOUTHWEST
AND SOUTH OF THE CWA THROUGH 12Z TUE. ONGOING EAST-SOUTHEASTERLIES
IN THE LLVLS WITH DRYING AFFECT MAY HAMPER MUCH OF ANY PRECIP EVEN
MAKING IT ACRS THE SOUTHERN CWA BEFORE DAYBREAK/LIKE THE NAM IS
ADVERTISING/...BUT SECONDARY FORCING WING AND SOME SATURATION TO
PROBABLY ALLOW FOR A BANDED RAIN EVENT MAKING IT ACRS THE SOUTHWEST
THIRD TO QUARTER OF THE CWA MAINLY AFTER 2 AM CDT. SFC TEMPS IN
THESE SOUTHERN AREAS MAY BE AROUND OR JUST UNDER FREEZING...ALONG
WITH SOME WET BULB ZERO CUSHION OF A FEW DEGREES TO ALLOW FOR A
WINDOW OF FREEZING RAIN AS THE PRECIP STARTS TO REACH THE SURFACE
LATE TONIGHT AND EARLY TUE MORNING AGAIN SOUTH OF I80 AND PROBABLY
SOUTH OF A WASHINGTON IA TO MONMOUTH IL LINE. BUT SFC TEMPS DOWN
THERE ALLOWED TO WARM INTO THE UPPER 30S TO AROUND 40 THIS
AFTERNOON...AS WELL AS A WARM AIR ADVECTION TYPE SCENARIO OVERNIGHT
MAKE FOR A MARGINAL ICING EVENT PROBABLY TO BE ABLE TO BE COVERED
WITH A SPECIAL WX STATEMENT AS OPPOSED TO AN ADVISORY. WILL KEEP
ISOLATED THUNDER IN THE FAR SOUTH TONIGHT WITH FIRST SURGE OF LIFT
BEFORE THE COLUMN SATURATES...BUT THE LACK OF INSTABILITY EVEN ALOFT
SUGGEST THIS THREAT AT THAT TIME LIMITED.

TUESDAY...THE BRIEF AND LIGHT ICING EVENT POSSIBLY TO MIGRATE NORTH
TO A TIER OF COUNTIES SOUTH OF I80 THROUGH MID MORNING BEFORE SFC
TEMPS AND DPTS IMPROVE/RISE ENOUGH TO MITIGATE ANY SUBSTANTIAL
ICING TROUBLE...ANY LINGERING THUNDER TO DROP OUT BY MID MORNING AS
WELL. DO LIKE THE LATEST WRF/S HANDLING OF SUGGESTING THAT THIS
WHILE THIS WING OF ELEVATED RAIN/SHOWERS LIFTS NORTH AND EAST...IT
TEMPORARILY PULLS AWAY FROM BETTER FEED AND SHOULD WANE BY MIDDAY.
EST TO SOUTHEAST SFC WINDS TO INCREASE AS THE DAY PROGRESSES AND
SFC LOW ROLLS OUT OF THE SOUTHERN PLAINS INTO WESTERN MO. THEN
SECONDARY AND STRONGER SURGE OF 45-55 KT H85 SOUTHERLY FLOW TO FUEL
AN ELEVATED THTA-E PLUME MORE CAPABLE OF SUPPORTING THUNDER ACRS THE
SOUTHWEST HALF FROM LATE AFTERNOON AND INTO TUE EVENING. ELEVATED MID
LAYER CAPES OF 250-500 J/KG AND BETTER MID LAYER LAPSE RATES. THE LOW
TO MID LEVEL SHEAR BECOMES VERY STRONG BY 00Z ACRS THE SOUTH HALF...
BUT THE STORMS SHOULD REMAIN ELEVATED. WILL HAVE TO STILL WATCH FOR A
FEW STORMS PRODUCING HAIL SA THEY QUICKLY MOVE UP OUT OF THE SOUTH
LATE TUE AFTERNOON. SFC TEMPS HELD IN THE 40S.    ..12..


.LONG TERM...(TUESDAY NIGHT THROUGH NEXT MONDAY)
ISSUED AT 334 PM CDT MON MAR 23 2015

THE MAIN STORM SYSTEM MOVES THROUGH THE AREA TUESDAY NIGHT. THE
OVERALL FORCING AND MOISTURE IS CONSIDERABLE WITH PLENTY OF WARM AIR
ALOFT. RAIN WILL BE SEEN ACROSS THE AREA DURING TUESDAY EVENING.
UNSTABLE AIR ALOFT SUPPORTS THE POTENTIAL FOR SOME ELEVATED
THUNDERSTORMS GENERALLY EAST OF AN OTTUMWA TO FREEPORT LINE.

AFTER MIDNIGHT THE BETTER FORCING ASSOCIATED WITH THE SURFACE LOW
MOVES EAST OF THE AREA. PRECIPITATION COVERAGE/INTENSITY WILL
DECREASE AND END WITH TIME FROM THE SOUTHWEST TO THE NORTHEAST. AS
COLDER AIR GETS PULLED DOWN BEHIND THE DEPARTING LOW...A RAIN/SNOW
MIX WILL BE POSSIBLE GENERALLY NORTH OF I-80 AND ALONG/WEST OF THE
MISSISSIPPI BEFORE ENDING. ANY SNOW ACCUMULATIONS SHOULD BE A TRACE
AT BEST.

DRY CONDITIONS SHOULD BE SEEN ON WEDNESDAY AS THE AREA IS BETWEEN
STORM SYSTEMS. CLOUD COVER WILL BE KEY AS TO HOW WARM IT WILL GET.
THE POTENTIAL IS THERE FOR A 15 TO POSSIBLY 20 DEGREE GRADIENT IN
TEMPERATURES FROM NORTH TO SOUTH ACROSS THE AREA WITH THE SOUTH HALF
BEING THE WARMEST.

WEDNESDAY NIGHT THE NEXT STORM SYSTEM PASSES TO THE SOUTH OF THE
AREA BUT THE SOUTHEAST THIRD WILL BE ON THE EDGE OF THE
PRECIPITATION SHIELD. AS SUCH LIGHT RAIN SHOULD BE SEEN GENERALLY
SOUTH OF AN OTTUMWA IOWA TO PRINCETON ILLINOIS LINE THAT MAY MIX
WITH SOME SNOW BEFORE ENDING AFTER MIDNIGHT.

DRY CONDITIONS WILL BE SEEN ACROSS THE AREA THURSDAY MORNING BEFORE
A WEAK UPPER LEVEL DISTURBANCE MOVES THROUGH THE AREA DURING THE
AFTERNOON. MOISTURE IS QUITE LIMITED WITH THIS DISTURBANCE BUT SOME
ISOLATED RAIN SHOWERS MAY BE POSSIBLE ACROSS THE FAR NORTHEAST
DURING THE AFTERNOON.

THURSDAY NIGHT ON...
THURSDAY NIGHT ANOTHER WEAK UPPER LEVEL DISTURBANCE WILL DROP INTO
THE GREAT LAKES. THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS OVER THE
FAR NORTHEAST AND EAST AREAS. MOISTURE IS LIMITED BUT IT MAY BE
ENOUGH TO GENERATE A RAIN/SNOW MIX THAT MIGHT CHANGE OVER TO ALL
SNOW IF TEMPERATURES GET COLD ENOUGH.

FRIDAY THROUGH SATURDAY THE MODEL CONSENSUS HAS DRY CONDITIONS AS
HIGH PRESSURE MOVES THROUGH THE MIDWEST. TEMPERATURES WILL AVERAGE
BELOW NORMAL.

SATURDAY NIGHT/SUNDAY ANOTHER COLD FRONT WILL SWEEP THROUGH THE
MIDWEST. AGAIN MOISTURE IS LIMITED SO VERY LITTLE PRECIPITATION
WOULD OCCUR. THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS SATURDAY
NIGHT AND OVER THE EASTERN HALF OF THE AREA ON SUNDAY.

SUNDAY NIGHT THROUGH MONDAY THE MODEL CONSENSUS HAS DRY CONDITIONS
AS THE NEXT HIGH PRESSURE BUILDS INTO THE MIDWEST. TEMPERATURES
SHOULD AVERAGE ABOVE NORMAL.    ..08..

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1240 PM CDT MON MAR 23 2015

VARYING CIGS THIS AFTERNOON IN THE WAKE OF THE PASSING CLIPPER
SYSTEM...SOME AFTERNOON RISES FROM MVFR TO LOW VFR POSSIBLE BUT
MAY KEEP MOST SITES AT MVFR THROUGH THE EVENING. THE CHALLENGE IS
TONIGHT WHEN SOME MODELS TEMPORARILY RISE CIGS TO VFR FROM MID
EVENING THROUGH TUE MORNING BEFORE THEY START TO DROP AGAIN BY
LATE MORNING AS A WING OF RAIN APPROACHES FROM THE SOUTHWEST. BUT
WITH INVERSION ALOFT...WILL PLAY IT MORE PESSIMISTICALLY AND TRAP
A MVFR BKN-OVC DECK AT MOST SITES FRO MUCH OF THE NIGHT. EAST TO
NORTHEAST SFC WINDS UNTIL TUE MORNING WHEN THEY TAKE ON A MORE
EAST-SOUTHEAST DIRECTION AND INCREASE TO 10-15KTS. CID AND DBQ
SHOULD STAY DRY UNTIL TUE AFTERNOON...MLI HAVE RAIN IN THE VCNTY
BY LATE MORNING. THE PROBLEM WILL BE AT BRL WHERE IF PRECIP MAKES
IT IN EARLY ENOUGH SAY AROUND 7-8AM CDT...SFC TEMPS MAY BE JUST
UNDER FREEZING AND THUS A LIMITED WINDOW FOR SOME FREEZING RAIN.
  ..12..

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...08
AVIATION...12





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