National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KDVN 152044
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
344 PM CDT WED MAY 15 2013

.SYNOPSIS...
ISSUED AT 341 PM CDT WED MAY 15 2013

A COLD FRONT SLOWLY PUSHED JUST SOUTH OF THE FORECAST AREA
TODAY...AND IS NOW DRAPED ACROSS NORTHERN MISSOURI INTO WEST CENTRAL
ILLINOIS. EARLIER TODAY SOME SCATTERED SHOWERS DEVELOPED ALONG THIS
BOUNDARY BUT HAVE SINCE DISSIPATED. ANOTHER BAND OF SHOWERS AND A
COUPLE THUNDERSTORMS HAVE BEEN DEVELOPING THIS AFTERNOON ALONG A MID
LEVEL BOUNDARY A BIT FURTHER NORTH ALONG A SIGOURNEY IOWA TO KEWANEE
ILLINOIS LINE. THOUGH NOT AS HOT AS YESTERDAY...TEMPERATURES BEHIND
THE FRONT STILL WARMED ABOVE NORMAL ACROSS THE FORECAST AREA INTO
THE UPPER 70S NORTH TO MIDDLE 80S SOUTH. INCREASING MID LEVEL
MOISTURE HAS BEEN SPREADING NORTHEAST WITH SOUTHWESTERLY FLOW FROM
TEXAS ACROSS MISSOURI...SOME OF WHICH HAS BEEN WORKING ITS WAY INTO
THE SOUTHERN PORTIONS OF THE FORECAST AREA AIDING IN THE MOST RECENT
PRECIPITATION ACTIVITY DEVELOPMENT ALONG THE MID LEVEL BOUNDARY.

STOFLET

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 341 PM CDT WED MAY 15 2013

MAIN FORECAST FOCUS THROUGH TOMORROW IS WITH PRECIPITATION
CHANCES...AS WELL AS TEMPERATURES THROUGHOUT.

THE COLD FRONT IS NOT EXPECTED TO MAKE MUCH FURTHER PROGRESS SOUTH
TONIGHT...AND STALL VERY CLOSE BUT JUST SOUTH OF THE FORECAST AREA.
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED TO DEVELOP IN
THE VICINITY OF THE FRONT AGAIN TONIGHT...AND MAY AFFECT THE FAR
SOUTHERN PORTIONS OF THE FORECAST AREA.

THE FORECAST MODELS ALSO SHOW ONGOING CONVERGENCE AND A POOL OF
MOISTURE ALONG THE MID LEVEL BOUNDARY ACROSS THE CENTRAL PORTION OF
THE FORECAST AREA INTO TONIGHT. SO AM THINKING WE MAY SEE
ADDITIONAL DEVELOPMENT OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS
ACROSS THE CENTRAL INTO SOUTHERN SECTIONS OF THE FORECAST AREA UNTIL
THE CONVERGENCE ALONG THE MID LEVEL BOUNDARY WEAKENS SUFFICIENTLY
LATER TONIGHT. SEVERE STORMS ARE NOT ANTICIPATED WITH EITHER OF
THESE AREAS OF DEVELOPMENT.

ONE LAST AREA OF PRECIPITATION FOCUS IS A BAND OF SHOWERS THAT
CONTINUES TO DEVELOP TO THE NORTH AND NORTHWEST OF THE FORECAST AREA
FROM CENTRAL IOWA ACROSS SOUTHERN WISCONSIN. AM NOT AS CONFIDENT
THAT THIS ACTIVITY WILL HOLD TOGETHER AS IT HEADS SOUTHEAST...BUT
CANNOT RULE OUT SOME LIGHT RAIN SHOWERS FOR THE NORTHERN FORECAST
SECTION EITHER AS WEAKNESS IN THE UPPER WESTERLY FLOW TRACK EASTWARD.

THE UPPER LOW WILL SLOWLY HEAD NORTHEAST FROM OKLAHOMA TOWARD
SOUTHERN MISSOURI THURSDAY. AS THIS FEATURE BEGINS TO PUSH
NORTHEAST...THE SURFACE FRONT JUST SOUTH OF THE AREA WILL BE FORCED
SLIGHTLY NORTHWARD AS A WARM FRONT TOMORROW. THE FORCING IS NOT
STRONG...BUT ONCE AGAIN WILL POSE THE CHANCE FOR SHOWER AND POSSIBLE
THUNDERSTORM ACTIVITY FOR MAINLY THE SOUTHERN PORTIONS OF THE
FORECAST AREA.

WITH ONLY SLIGHT CHANGES TO THE AIRMASS FROM NOW THROUGH
TOMORROW...TEMPERATURES SHOULD FEEL PRETTY SIMILAR TO TODAY EXCEPT
FOR MAYBE THE SOUTHERN FORECAST SECTION WHERE THEY WILL NOT BE QUITE
AS WARM. OVERNIGHT LOW TEMPERATURES TONIGHT ARE FORECAST TO FALL
INTO THE MIDDLE 50S TO LOWER 60S. HIGH TEMPERATURES TOMORROW ARE
FORECAST AROUND 80 DEGREES.

STOFLET


.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 341 PM CDT WED MAY 15 2013

CONTINUED NEAR TO ABOVE NORMAL TEMPERATURES AND A TRANSITION TO MORE
ACTIVE WEATHER ARE THE HIGHLIGHTS OF THE EXTENDED. ALTHOUGH LOW
PROBABILITIES FOR SHOWERS AND THUNDERSTORMS ARE IN THE FORECAST FOR
NEARLY EVERY PERIOD...THE BEST CHANCES ARE FOCUSED ON TWO SYNOPTIC
SYSTEMS. THE FIRST IS THE NORTHWARD LIFTING WARM FRONT LATE THU NIGHT
INTO FRIDAY. THE SECOND IS A DEVELOPING LOW PRESSURE SYSTEM IN THE
PLAINS THAT BECOMES NEARLY STATIONARY...SETTING UP SEVERAL DAYS OF
GREATER THUNDERSTORMS CHANCES AND POTENTIAL FOR SEVERE STORMS
SUNDAY THROUGH AT LEAST MONDAY NIGHT.

THURSDAY NIGHT...THE REMNANTS OF THE WEAKENING UPPER LEVEL WAVE
PASSING TO THE SOUTH...AND A SEPARATE SHORTWAVE MOVING OUT OF THE
CENTRAL PLAINS WILL PROVIDE MID LEVEL FORCING AND ALSO NUDGE THE
STATIONARY SURFACE FRONT NORTHWARD AS A WARM FRONT. THE CHALLENGE
WILL BE HOW FAR NORTH THIS BOUNDARY CAN ADVANCE BEFORE STALLING...
LIKELY SOMEWHERE OVER THE NORTHERN HALF OF THE FORECAST AREA EARLY
FRIDAY...AS IT NUDGES UP AGAINST THE ANTICYCLONIC FLOW OUT OF HIGH
PRESSURE IN PLACE OVER THE UPPER GREAT LAKES. AT THIS TIME...THE LOW
LEVEL JET DRIVING THE THETAE ADVECTION IS UNIMPRESSIVE...AND MORE
STRONGLY FOCUSED WELL THE WEST TOWARD THE MO RIVER VALLEY. WILL THUS
KEEP POPS IN A CHANCE RANGE FOR OVERNIGHT INTO FRIDAY...WHEN
ADDITIONAL REDEVELOPMENT WILL BE POSSIBLE WITH DAYTIME INSTABILITY
OVER ESPECIALLY THE NORTH. WITH A STRENGTHENING EASTERLY FLOW NORTH
OF THIS BOUNDARY PULLING IN A GREAT LAKES AIRMASS...HAVE GONE WITH
LOWS IN THE 50S NORTH OF I-80 AND LOWER 60S SOUTH. HIGHS FRIDAY WILL
BE GREATLY DEPENDENT ON WHERE THE NW TO SE ORIENTED WARM FRONT
STALLS. FOR NOW...HAVE A COMPROMISE RANGE FROM THE LOWER 70S
NORTHEAST TO UPPER 70S SOUTH.

FRIDAY NIGHT THROUGH SATURDAY NIGHT...THE SURFACE BOUNDARY SLOWLY WEAKENS
AS THE GREAT LAKES HIGH RETREATS EASTWARD AND LOW PRESSURE FORMS IN
THE PLAINS. A BUILDING UPPER LEVEL RIDGE OVER THE CENTRAL U.S. AND
WARMING TEMPERATURES ALOFT WILL LIKELY CAP OFF CONVECTION.
CONSIDERING THIS...AND THE LACK OF STRONG SURFACE BOUNDARIES...HAVE
ONLY SLIGHT CHANCES FOR THUNDERSTORMS THROUGHOUT. AN OPEN FLOW FROM
THE GULF OF MEXICO WILL ADVECT A SUMMERLIKE LOW LEVEL AIRMASS WITH
HIGHER HUMIDITY AND ABOVE NORMAL TEMPERATURES WITH HIGHS IN THE 80S
AND LOWS IN THE 60S.

SUNDAY THROUGH WEDNESDAY...A SURFACE AND UPPER LEVEL LOW DEVELOP OVER
THE NORTHERN PLAINS ENHANCING THE NORTHERLY FEED OF MOISTURE INTO
THE MS VALLEY AND SENDING A SERIES OF BOUNDARIES THROUGH THE REGION
BEFORE EXITING AROUND MID WEEK. WITH THE HIGH LEVELS OF MOISTURE...
HEAVY RAIN WILL BE A THREAT BY SUNDAY NIGHT WHEN THE UPPER LEVEL CAP
WEAKENS AND ORGANIZED COMPLEXES MAY DEVELOP. THERE WILL ALSO BE A
THREAT OF SEVERE STORMS...ESPECIALLY SUNDAY NIGHT INTO MONDAY. SPC/S
4-6 DAY OUTLOOK HAS OUTLINED A LARGE PORTION OF THE CENTRAL PLAINS
AND MID MS VALLEY...WHICH BY MONDAY...OR DAY 6...REACHES INTO THE
SOUTHERN HALF OF THE LOCAL FORECAST AREA. IN THIS PERIOD...
SUFFICIENT SHEAR AND INSTABILITY MAY OVERLAP TO BRING A SIGNIFICANT
THREAT FOR STORMS WITH LARGE HAIL...DAMAGING WIND AND POSSIBLY
TORNADOES. BY TUESDAY INTO WED...THERE IS LITTLE AGREEMENT IN HOW
THIS SYNOPTIC SYSTEM BREAKS DOWN AND TRANSITIONS E-SE OUT OF THE
REGION. FOR NOW...WILL FOLLOW BLENDS THAT KEEP LOW CHANCES FOR
SHOWERS AND POSSIBLE THUNDERSTORMS GOING TUE INTO WED WITH
TEMPERATURES TRENDING CLOSER TO TYPICAL LATE MAY VALUES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1256 PM CDT WED MAY 15 2013

PREDOMINANTLY VFR CONDITIONS EXPECTED THROUGH THURSDAY MORNING.
A WEAK COLD FRONT CONTINUES TO SAG SOUTH NEAR THE IOWA/MISSOURI
BORDER...HAVING RECENTLY PASSED TO THE SOUTH OF KBRL. THE FRONT IS
EXPECTED TO PUSH SOUTHWARD ONLY SLIGHTLY...BEFORE SHIFTING
NORTHWARD AGAIN TOMORROW. A COUPLE BANDS OF SCATTERED SHOWERS HAVE
DEVELOPED IN THE VICINITY OF THE FRONT TODAY. SCATTERED SHOWER
ACTIVITY IS EXPECTED TO CONTINUE THROUGH TOMORROW...WITH THE BEST
CHANCES ACROSS SOUTHEAST IOWA AND WEST CENTRAL ILLINOIS. ISOLATED
THUNDERSTORMS ARE ALSO POSSIBLE. KEPT WITH VCSH FOR KBRL SINCE
CONFIDENCE FOR STORMS AT ANY INDIVIDUAL LOCATION IS LOW. WINDS
BEHIND THE FRONT ARE GENERALLY FROM THE NORTH AND ARE EXPECTED TO
BE AROUND 10KTS THROUGH THE AFTERNOON...AND DECREASE LATER THIS
EVENING.

STOFLET

&&

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

$$

SYNOPSIS...STOFLET
SHORT TERM...STOFLET
LONG TERM...SHEETS
AVIATION...STOFLET