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000
FXUS63 KDVN 141743
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1243 PM CDT TUE MAY 14 2013

.UPDATE...
ISSUED AT 654 AM CDT TUE MAY 14 2013

HAVE SENT OUT A QUICK UPDATE TO FRESHEN UP TEMPERATURES THIS
MORNING. OVERNIGHT MINIMUM TEMPERATURES WERE WARMER THAN
PREVIOUSLY FORECAST...SO HAVE WARMED UP THE MORNING TEMPERATURES
TO REFLECT THIS CHANGE. HAVE NOT MADE ANY CHANGES TO MAX TEMP THIS
AFTERNOON AT THIS TIME.

&&

.SYNOPSIS...
ISSUED AT 345 AM CDT TUE MAY 14 2013

BROAD SOUTH TO SOUTHWEST FLOW IS OVER THE MIDWEST THIS
MORNING...WITH A SURFACE LOW OVER SOUTHEAST MONTANA.  A WEAK WARM
FRONT IS CURRENTLY PASSING NORTHEAST ACROSS THE CWA AND UP INTO
WISCONSIN...WITH A PRESSURE FALL MAXIMA OVER LAKE MICHIGAN
INDICATING THAT IT IS MOVING SLOWLY EAST.  THE FRONT IS SOMEWHAT
BROAD IN NATURE AND IS DIFFICULT TO PICK OUT AT THE SURFACE...EXCEPT
WHERE THE TEMPERATURES ARE SLOWLY RISING ON THE SOUTHWEST SIDE OF IT.
AT UPPER LEVELS...THE 00Z ANALYSIS SHOWS STRONG WARM AIR ADVECTION
ONGOING AT 850MB...WITH JUST +7C OVERHEAD...TO +18C AT KOAX AND KTOP
TO +25C AT KDDC AND KLBF...ALL WITH SOUTHWEST WINDS OF 20-30KTS. WE
HAVE A BROAD UPPER LEVEL RIDGE AT 500MB WITH A WEAK CUT OFF LOW OVER
NORTHERN MEXICO.  YESTERDAY HIGH TEMPERATURES IN WESTERN KANSAS AND
EASTERN NEBRASKA WERE IN THE UPPER 80S TO LOW 90S...WITH LOW TO MID
80S OVER EASTERN KANSAS AND WESTERN IOWA.   LE

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT TUE MAY 14 2013

MAIN CONCERN TODAY IS THE TEMPERATURES AND DEWPOINTS FOR
TODAY...THEN SHOWER AND THUNDERSTORM POTETIAL FOR TONIGHT.

THE GREAT DEBATE OVER THE LAST COUPLE DAYS HAS BEEN HOW WARM WE ARE
GOING TO GET TODAY.  MODELS ARE STILL SHOWING THE POTENTIAL FOR A
BIG WARM-UP TODAY...BRINGING THOSE VERY WARM 850MB TEMPERATURES OF
+22 TO +24 OVER THE AREA...WHICH IS QUITE REASONABLE GIVEN LAST
EVENINGS SOUNDINGS OVER THE PLAINS...BUT UP ABOVE THE 99TH
PERCENTILE OF 850MB TEMPERATURES FOR THIS TIME OF YEAR.  IF WE WERE
TO MIX ALL THE WAY TO 850MB...THIS WOULD PUT OUR HIGH TEMPERATURES
INTO THE MID TO UPPER 90S.  HOWEVER...WE ARE NOT LIKELY TO MIX THAT
DEEPLY.  THE WARM LAYER ALOFT IS GOING TO SERVE AS A CAP ON ANY SORT
OF CONVECTION...AND LIKELY OUR MIXING IS GOING TO BE KEPT DOWN BELOW
900MB OR EVEN 925MB.  OUR SOUNDING TOMORROW EVENING IS LIKELY TO
LOOK A LOT LIKE LAST EVENINGS KTOP SOUNDING WITH THE CAP BETWEEN 850
AND 900 MB...AND THE BOUNDARY LAYER ALL BELOW 900MB.  THUS...AS A
BETTER INDICATION OF TODAYS MAX TEMPS HAVE GONE WITH THE 925MB
TEMPERATURES...AND WHILE THEY ARE ALSO QUITE WARM GIVE US MAX TEMPS
IN THE MID 80S NORTHEAST TO AROUND 90 IN THE SOUTHWEST.  DEWPOINTS
FOR TODAY HAVE ALSO BEEN A SOURCE OF CONSTERNATION.  MODELS HAVE
BEEN CONSISTENTLY BLOOMING DEWPOINTS OVER THE AREA BETWEEN 12Z AND
18Z...RISING APPROXIMATELY 10 DEGREES DURING THAT TIME FRAME.
HOWEVER...THIS IS QUITE UNREALISTIC. THE MODELS APPEAR TO BE
PRODUCING A SIGNIFICANT AMOUNT OF MOISTURE FROM CROPS.
HOWEVER...THESE ARE FAR BEHIND THEIR NORMAL...WITH LESS THAN 15
PERCENT OF THE CORN CROP PLANTED AS OF MONDAY...MUCH LESS EMERGED
AND GROWING STRONGLY.  NORMALLY WE WOULD HAVE 80 PERCENT OF THE CORN
PLANTED AND 30 PERCENT OF IT WOULD BE EMERGED AND PRODUCING LOCALLY
HIGHER DEWPOINTS.   YESTERDAY IN EASTERN KANSAS DEWPOINTS GOT NO
HIGHER THAN UPPER 50S TO AROUND 60...WHERE THEIR CROPS ARE ONLY A
LITTLE FARTHER ALONG THAN OURS ARE.  MODELS OVERDID THIS
TOO...RUNNING AT ABOUT 5 DEGREES TOO HIGH IN NORTHEAST KANSAS.  WITH
THAT SAID...AM KEEPING DEWPOINTS IN THE LOW TO MID 50S TODAY...WELL
BELOW GUIDANCE VALUES RANGING FROM THE LOW 60S TO LOW 70S.

TONIGHT IS A BIT LESS CONTROVERSIAL.  WITH THE DEWPOINTS COMING IN
MUCH LOWER THAN GUIDANCE...THERE IS GOING TO BE LESS MOISTURE
AVIALABLE FOR SHOWERS AND THUNDERSTORMS EVEN AS THE COLD FRONT
SLOWLY DROPS SOUTHEAST THROUGH THE AREA.  THAT SAID...HAVE
MAINTAINED SOME SLIGHT CHANCE POPS FOR OVERNIGHT IN THE VICINITY OF
THE FRONT.  THE AIRMASS BEHIND THE FRONT IS NOT DRAMATICALLY
COLDER...SO HAVE KEPT MIN TEMPS IN THE UPPER 50S AND LOWER 60S.

LE

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 345 AM CDT TUE MAY 14 2013

WEDNESDAY AND THURSDAY...MOST OF LATEST RUN 00Z RUN MODELS
AGREE ON WEST-TO-EAST ORIENTED LLVL/SFC BOUNDARY TO SAG SOUTH ACRS
THE FAR SOUTHERN CWA AND ALONG THE IA/MO BORDER THROUGH WED EVENING.
MODELS DO VARY ON SOME THERMODYNAMIC PARAMETERS AS WELL AS
MOISTURE LEVELS/MOST MODELS APPEAR TOO HIGH...WITH BETTER/DEEPER
MOISTURE PROFILES PROBABLY REMAINING OFF TO THE SOUTHWEST TO LEE OF
SOUTHERN PLAINS LOW. THUS MOISTURE CONVERGENCE NOT GREAT IN THE
LOCAL AREA DURING THE DAY WED BUT WILL CARRY LOW CHC POPS FOR
SHOWERS AND PERHAPS A THUNDERSTORM ALONG THE FRONT. FCST SOUNDING
SUGGEST STRONG CAP/INVERSION WILL ALSO LIMIT ANY CONVECTION DURING
THE DAY WITH LACK OF FORCING. WILL GO WITH UPPER 70S NORTH OF I80 AND
THE LOWER 80S TO THE SOUTH...BUT IF MORE SUNSHINE AND LACK OF PRECIP
OCCURS THESE VALUES WILL BE TOO COOL BY A FEW DEGREES. NOCTURNAL
PROCESSES AND A 20-25 KT LLJ CONVERGING ON THE BOUNDARY WILL HAVE A
BETTER CHANCE OF PRODUCING ELEVATED SHOWERS AND STORMS SOUTH OF I80
LATER WED NIGHT INTO EARLY THU MORNING...MAY EVEN BE A SMALL MCS
TYPE FORMATION WITH RAINFALL OF A QUARTER UP TO A HALF INCH IN
THESE AREAS BY 12Z THU MORNING. THE BOUNDARY WILL LOOK TO UNDULATE
AND TRY TO RETREAT NORTHWARD ON THU TO I80 BUT UPPER RIDGING ACRS
THE UPPER MS RVR VALLEY AND LLVL RIDGING ACRS THE WESTERN GRT LKS
MAY INHIBIT IT FROM MAKING MUCH PROCESS. MARGINAL FORCING ON THU
ALONG THE FEATURE BUT ENOUGH TO KEEP MENTION OF SHOWERS AND STORMS.
CURRENTLY INDICATED THERMODYNAMIC PROFILES AND FORCING SHOULD
PRECLUDE MUCH OF ANY SVR STORM THREAT THIS PERIOD. AGAIN NOCTURNAL
PROCESSES MAY BE OF BETTER SUPPORT FOR MORE SHOWER/STORM ACTIVITY
THU NIGHT AS OPPOSED TO DURING THE DAY WITH BEST SHOT ALONG THE I80
CORRIDOR ALONG AND NORTH OF LLVL THTA-E RIBBON/GRADIENT. WILL
ADVERTISE WIDESPREAD UPPER 70S ON THU FOR HIGHS...BUT AGAIN MAY BE
ERRING ON THE COOL SIDE.

FRIDAY AND SATURDAY...PREFER THE NEW 00Z RUN ECMWF THIS PERIOD WHICH
SUGGESTS UPPER RIDGE TO GET SQUEEZED/AMPLIFIED UP ACRS THE MID AND
UPPER MS RVR VALLEY REGIONS AS WEST COAST L/W TROF MIGRATES
EASTWARD TO AND OVER THE ROCKIES THROUGH THE PERIOD. THE EURO ALSO
SUGGESTS MUCH OF THIS PERIOD COULD BE MAINLY DRY WITH A FEW
LOCALIZED AREAS GETTING SOME SHOWERS AND STORMS ALONG THE LINGERING
BOUNDARY OR RIDGE RIDING VORT/MCV. THE 00Z ECMWF SUGGESTS BEST
CHANCES FOR EVEN THIS TO THE NORTH AND JUST TO THE SOUTH OF THE DVN
CWA THROUGH SAT. BUT WITH UNCERTAINTY AND HANDLING OF THESE
FEATURES AT THIS POINT...WILL HAVE TO KEEP BLANKET CHC POPS GOING.
TEMPS COULD MODERATE BACK WELL INTO THE 80S BY SAT ESPECIALLY IN
THE SOUTH. THE 00Z GFS IS CONVECTIVELY FEEDBACK POLLUTED ACRS THE
CWA ON SAT WITH A HEAVY RAIN PRODUCING MCS.

SUNDAY INTO MONDAY...POTENTIALLY A STRONG TO SVR STORM EPISODE
SOMEWHERE IN THIS WINDOW AS THE MAIN UPPER TROF LIFTS OUT OF THE
SOUTHERN AND CENTRAL PLAINS AND POSSIBLY BECOMES NEG TILTED. MUCH
WILL DEPEND ON UPPER LEVEL JET ENERGY PLACEMENT ASSOCIATED WITH
THIS PROCESS...AS WELL AS BUILDING THERMODYNAMICS/HEATING TO
DRIVE THE NECESSARY INSTABILITY. THE NEW ECMWF DEVELOPS STRONG
STORMS ACRS CENTRAL IA SUNDAY AFTERNOON AND EARLY EVENING...WITH
THEM THEN PROPAGATING ACRS THE DVN CWA SUNDAY NIGHT IN A FORM OF AN
MCS. IF STORMS HOLD OFF LONG ENOUGH...EXTENT OF PRE-SYSTEM WAA
WOULD SUPPORT HIGHS IN THE UPPER 80S. IF WE GET THE HIGH ENOUGH
DEWPOINTS...THE AIRMASS WILL SUPPORT STRONG TO SVR STORMS IN THE
LOCAL AREA AS WELL SUNDAY EVENING. THE EURO THEN DRY SLOTS THE CWA
FOR LATE SUNDAY NIGHT INTO MON. BUT IT ALSO HANGS BACK THE UPPER TROF
IN A WAY THAT IT MAY IGNITE MORE STORMS IN OR CLOSE TO THE CWA/EAST
AND SOUTH/ MONDAY NIGHT. THE 00Z GFS IS SLOWER AND TARGETS MONDAY AND
MONDAY NIGHT AS THE CONVECTIVE WINDOW. THE NEW 00Z RUN UKMET AT 144
HRS IS MORE IN LINE WITH THE ECMWF. WILL HAVE TO MAINTAIN HIGH CHC
POPS THOUGH THESE EXTENDED RANGE DAYS UNTIL MORE REFINEMENT CAN BE
DONE. THE LONG WAVE TROF TO BECOME COLD CORE WITH ANOTHER POSSIBLE
BIG COOL DOWN BY MID NEXT WEEK/TUE INTO WED/.    ..12..

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1230 PM CDT TUE MAY 14 2013

CONDITIONS TO REMAIN VFR THROUGH THE PERIOD. FAIR SKIES AND WARM TO
VERY WARM TODAY AHEAD A WEAK CO9OL FRONT THAT WILL PASS OVERNIGHT.
SOUTHWEST WINDS OF 5 TO 15 KTS WILL SHIFT TO THE NORTHWEST BETWEEN
15/08-13Z WEDNESDAY. A FEW ISOLATED THUNDERSTORMS MAY FIRE ALONG
THE FRONT OVERNIGHT INTO EARLY WEDNESDAY. THE CHANCES ARE TOO
SMALL TO INCLUDE IN THE TAF FORECASTS AT THIS TIME.

NICHOLS

&&

.CLIMATE...
ISSUED AT 345 AM CDT TUE MAY 14 2013
RECORD HIGHS FOR TODAY. THESE ARE JUST FOR YOUR INFORMATION...DO
NOT EXPECT TO BREAK ANY OF THESE TODAY.

RECORD HIGHS FOR MAY 14...

MOLINE.........93 IN 2007
CEDAR RAPIDS...93 IN 1932
DUBUQUE........92 IN 1932
BURLINGTON.....92 IN 1932

&&

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

$$

UPDATE...LE
SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...12
AVIATION...NICHOLS
CLIMATE...LE