000
FXUS63 KDVN 150448
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1148 PM CDT FRI JUN 14 2013

.UPDATE...
ISSUED AT 937 PM CDT FRI JUN 14 2013

SMALL BOWING MCS INTO SOUTHWEST IA SHOULD BEGIN SHIFT/MOVE E/SE
ALONG LOW LEVEL MOISTURE AND INSTABILITY GRADIENT THROUGH
LATE EVENING... WITH ATTENDANT ELEVATED WARM ADVECTION WING OF
CONVECTION OUT AHEAD SHIFTING SLOWLY EASTWARD. APPARENT MCV
MOVING THROUGH WEST CENTRAL IA SHOULD MOVE EAST OVERNIGHT AND
COUPLED WITH SOUTHWESTERLY LOW LEVEL JET AND STRONG CONVERGENCE
ON NOSE INTO EASTERN IA ALL SUPPORTIVE OF INCREASING COVERAGE
OF SHOWERS AND STORMS INTO THE OVERNIGHT. MAIN THREAT WILL BE
HEAVY RAIN WITH HIGH PWATS OF 1.5-1.8 INCHES AND FAIRLY SLOW
STORM MOTIONS... REFERENCE 00Z DVN RAOB WHICH SHOWS AROUND
15 KTS OF WIND THROUGH MID LEVELS OF ATMOSPHERE. THE SOUTHWESTERLY
ORIENTATION OF LOW LEVEL JET IS A BIT CONCERNING FOR BACKBUILDING
OR CONTINUED STORM DEVELOPMENT... AND THU CANT RULE OUT SOME
LOCALIZED SWATHS OF 1-2+ INCHES OVERNIGHT INTO SAT AM. ATTM THE
MOST FAVORED AREAS FOR HEAVIEST RAINS WOULD APPEAR TO BE WEST AND
SOUTHWEST SECTIONS OF CWA.

&&

.SYNOPSIS...
ISSUED AT 235 PM CDT FRI JUN 14 2013

MCS THAT HAS MOVED ACROSS SOUTHEAST IA/NORTHEAST MO THIS AFTERNOON
CONTINUES TO PUSH SLOWLY TO THE SOUTHEAST WHILE GRADUALLY
WEAKENING. THERE WAS ALSO A LINE OF THUNDERSTORMS IN NORTHWEST IA.
CURRENT TEMPERATURES WERE IN THE 70S ACROSS THE DVN CWA BUT WERE
AROUND 100 IN WESTERN KS. A TONGUE OF 70+ SURFACE DEWPOINTS EXTENDED
FROM EAST TX INTO EASTERN NEB.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 235 PM CDT FRI JUN 14 2013

FORECAST FOCUS ON INCREASING THUNDERSTORM CHANCES AND THE
POTENTIAL FOR SEVERE WEATHER ON SATURDAY.

TONIGHT...WITH A WEAK LOW LEVEL JET AND INCREASING MOISTURE WILL
CONTINUE WITH CHANCE POPS THIS EVENING FOR SHOWERS AND THUNDERSTORMS.
HOWEVER...AS THE LOW LEVEL JET STRENGTHENS TONIGHT ELEVATED
THUNDERSTORMS IN THE FORM OF A MCS SHOULD DEVELOP ACROSS MUCH OF
THE DVN CWA ESPECIALLY AFTER MIDNIGHT. A SHORT WAVE ALSO RIDES THE
TOP OF THE RIDGE TO CREATE VERTICAL MOTION. PRECIPITABLE WATERS
INCREASE TO 1.90 INCHES BY MORNING SO THE STRONGER STORMS WILL
PRODUCE HEAVY RAINFALL. BECAUSE WE HAVE BEEN DRY LATELY THE SOILS
SHOULD BE ABLE TO ABSORB MOST OF THIS RAINFALL SO NOT EXPECTING
HYDRO ISSUES. NONETHELESS SOME LOCATIONS MAY RECEIVE 1 TO 2 INCHES
OF RAINFALL. FREEZING LEVELS WILL BE RATHER HIGH AND BECAUSE THE
COLUMN MOISTENS QUITE A BIT LATER TONIGHT THE THREAT OF HAIL
APPEARS LOW AT THIS TIME. MINIMUM TEMPERATURES WILL BE IN THE
LOWER TO MID 60S.

SATURDAY...THE ENTIRE CWA IS IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS.
ELEVATED THUNDERSTORMS IN THE FORM OF A MCS SHOULD BE DIMINISHING IN
THE MORNING WITH THE LOW LEVEL JET WEAKENING. HOWEVER...DURING THE
AFTERNOON THE POTENTIAL FOR SURFACE BASED THUNDERSTORMS WILL
INCREASE AS A WARM FRONT LIFTS INTO THE CWA...AND A COLD FRONT
APPROACHES FROM THE NORTHWEST. DEWPOINTS RISING TO AROUND 70 AND
TEMPERATURES PUSHING TO 80+ AT MOST LOCATIONS SHOULD YIELD MLCAPES
OF UP TO 2500 J/KG LATER IN THE AFTERNOON. MODERATE SHEAR WILL BE
IN PLACE SO THE KEY WILL BE AMOUNT OF CLOUD DEBRIS LEFTOVER FROM
THE MORNING MCS AND THE PLACEMENT OF THE WARM FRONT. AT THIS POINT
THE GREATEST INSTABILITY WILL BE ACROSS SOUTHEAST IA/NORTHEAST MO
AND WESTERN IL AS TEMPERATURES PUSH INTO THE MID 80S AND DEWPOINTS
RISE INTO THE LOWER 70S. INTERESTING TO NOTE THE MODELS INDICATE A
50 KNOT MID LEVEL SPEED MAX ARRIVING DURING THE LATE AFTERNOON AND
EVENING WHICH SHOULD ENHANCE THE DEEP LAYER SHEAR AND INCREASE THE
DAMAGING WIND THREAT. OTHERWISE INITIALLY THERE WILL BE A SUPERCELL
POTENTIAL NEAR THE WARM FRONT ALLOWING FOR POSSIBLE ISOLATED
TORNADOES AND LARGE HAIL. ONCE AGAIN THE KEY WILL BE CLOUD TRENDS
AND PLACEMENT OF THE WARM FRONT.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 235 PM CDT FRI JUN 14 2013

SATURDAY NIGHT THROUGH SUNDAY THE REGION WILL BE UNDER BROAD WSW MID
LEVEL FLOW. MODELS CONTINUE TO SHOW A MOIST UNSTABLE AIRMASS
REMAINING IN PLACE AND SUBTLE IMPULSES MOVING THROUGH THE MID LEVEL
FLOW ALONG WITH A WEAK SURFACE BOUNDARY MOVING THROUGH THE SOUTHERN
SECTIONS OF THE FORECAST AREA.  HAVE CONTINUED WITH BROAD BRUSH
CHANCE TO LIKELY POPS FOR THE SATURDAY NIGHT AND FOCUSED THE HIGHEST
POPS IN THE SOUTH WHERE THE BOUNDARY SHOULD BE LOCATED.  HEAVY RAIN
WILL BE A CONCERN WITH PW/S EXCEEDING 1.5 INCHES.  HOWEVER WITH
LACK OF A SIGNIFICANT FOCUS IN THE LOW LEVELS THE RISK OF ORGANIZED
WIDESPREAD HEAVY RAIN WILL BE LOW.  A LOW RISK OF SEVERE STORMS WILL
ALSO REMAIN OVER THE AREA WITH HIGH CAPES AND MODERATE DEEP LAYER
SHEAR. SUNDAY THE BOUNDARY SHOULD BE SOUTH OF THE AREA WITH WEAK
RIDGING BUILDING IN.  KEPT CHANCE POPS SOUTH AND SLIGHTS NORTH WITH
AN UNSTABLE AIRMASS STAYING OVER THE AREA AND SOME UNCERTAINTY ON
HOW FAR SOUTH THE BOUNDARY WILL BE DURING THE DAY.

SUNDAY NIGHT AND MONDAY A S/W DROPS SOUTHEAST OUT OF SOUTHERN CANADA
AND PUSHES A COLD FRONT THROUGH THE REGION BY LATE MONDAY
AFTERNOON.  WILL CONTINUE WITH CHANCE POPS OVER THE AREA WITH THIS
FEATURE. THE EARLY DAY TIMING WILL BE UNFAVORABLE FOR MUCH OF A
SEVERE THREAT.

TUESDAY AND WEDNESDAY SHOULD BE DRY WITH COMFORTABLE TEMPERATURES
AND HUMIDITIES WITH THE REGION SITTING UNDER NORTHWEST FLOW AND A
LARGE AREA OF HIGH PRESSURE OVER THE WESTERN GREAT LAKES. BY
THURSDAY THOUGH THE RIDGE STARTS TO WEAKEN AS A TROF DEVELOPS/MOVES
INTO THE PACIFIC NORTHWEST.  THIS WILL BRING THUNDERSTORMS CHANCES
BACK FOR THURSDAY AND FRIDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1135 PM CDT FRI JUN 14 2013

TIMING OF PRECIPITATION THE MAIN CHALLENGE WITH 06Z TAFS. BOWING
LINE OF STORMS CURRENTLY OVER SOUTH CENTRAL INTO SOUTHWEST
IOWA WILL LIKELY INTERRUPT LOW LEVEL JET INTO EASTERN IOWA FOR AS
LONG AS THE LINE CONTINUES. FAIRLY LARGE STRATIFORM RAIN SHIELD
WITH EMBEDDED STORMS OVER CENTRAL INTO NORTHERN IOWA MOVING
EASTWARD WITH AN APPARENT CONVECTIVELY ENHANCED SHORTWAVE.
THUS... DESPITE INTERRUPT OF LOW LEVEL JET... SUFFICIENT FORCING
FROM AFOREMENTIONED WAVE SHOULD ALLOW FOR INCREASE IN RAIN WITH
SOME STORMS OVERNIGHT. IF SOUTHERN IOWA LINE WEAKENS ALLOWING
LOW LEVEL JET TO IMPINGE ON EASTERN IOWA THEN STRONG CONVERGENCE
AND MOISTURE TRANSPORT COULD LEAD TO INTENSIFICATION OF CONVECTION
OVER AREA LATER TONIGHT UNTIL MID MORNING SATURDAY...WITH LOCALLY
HEAVY RAINS. ANTICIPATE A BREAK OR RELATIVE LULL IN PRECIPITATION
BY MIDDAY WITH ADDITIONAL DEVELOPMENT BY MID AFTERNOON INTO SATURDAY
EVENING AHEAD OF NEXT DISTURBANCE. POTENTIAL EXISTS FOR SOME SEVERE
STORMS. UNCERTAINTY WITH COVERAGE AND LOCATION AND THUS VCTS MENTION
DURING THE AFTERNOON AND EVENING AT ALL SITES. OVERALL... EXPECT
MVFR TO POSSIBLY IFR CONDITIONS ESPECIALLY FOR VSBYS WITH ANY
STORMS OTHERWISE...VFR CONDITIONS TO PREVAIL. WINDS LIKELY TO
FAVOR SOUTHERLY THROUGH SATURDAY EXCEPT VARIABLE IN STORMS. COULD
SEE SOME GUSTS BY AFTERNOON. SATURDAY NIGHT WINDS SHOULD BECOME
LIGHT AND SHIFT TO WESTERLY.

&&

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

$$

UPDATE...05
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...DLF
AVIATION...05