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000
FXUS63 KDVN 132357
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
657 PM CDT THU JUN 13 2013

.SYNOPSIS...
ISSUED AT 255 PM CDT THU JUN 13 2013

HIGH PRESSURE RIDGE OVER THE REGION PROVIDING A RATHER PLEASANT
AFTERNOON WITH NEAR NORMAL TEMPERATURES AND COMFORTABLE HUMIDITY...
ALONG WITH A REFRESHING NORTH WIND AT 10 TO 15 MPH. OTHER THAN
SCATTERED HIGH BASED CUMULUS CLOUDS THERE WAS PLENTY OF SUNSHINE.
CURRENT TEMPERATURES IN THE DVN CWA WERE MAINLY IN THE UPPER 70S
TO LOWER 80S. ELSEWHERE...READINGS WERE WELL INTO THE 90S ACROSS
THE SOUTHERN PLAINS AND LOWER MS VALLEY. THUNDERSTORMS WERE
LOCATED IN EASTERN NEBRASKA.

12Z SUBJECTIVE UPPER AIR ANALYSIS INDICATES THE NEXT SIGNIFICANT
TROUGH PUSHING INTO THE PACIFIC NORTHWEST. THERE IS PLENTY OF LOW
LEVEL MOISTURE WAITING IN THE WINGS ACROSS THE SOUTHERN PLAINS WITH
850 MB DEWPOINTS OF AT LEAST 14C AND AS HIGH AS 18C AT KMAF IN
WEST TX.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 255 PM CDT THU JUN 13 2013

FORECAST FOCUS ON A CHANCE OF THUNDERSTORMS LATE ON FRIDAY.

TONIGHT...SCATTERED CUMULUS CLOUDS WILL DISSIPATE EARLY THIS
EVENING WITH LOSS OF HEATING. OTHERWISE A CLEAR NIGHT WITH LIGHT
WINDS UNDER A HIGH PRESSURE RIDGE...WHICH SHOULD PROVIDE IDEAL
RADIATIONAL COOLING. SURFACE PARCEL TRAJECTORIES WILL BE COMING
FROM SOUTHERN MN WHERE TEMPERATURES EARLY THIS MORNING WERE IN THE
MID TO UPPER 50S. THEREFORE...I WILL FORECAST SIMILAR READINGS
HERE BY MORNING.

FRIDAY...THE BRIEF RESPITE FOR THE WEARY ENDS ALREADY BY LATE IN
THE AFTERNOON AS A RETURNING WARM FRONT AND DEEPER MOISTURE SPREAD
THUNDERSTORMS BACK INTO PORTIONS OF THE MIDWEST. THE BETTER
FORCING APPEARS TO BE MAINLY TO OUR WEST BUT WILL CARRY SMALL POPS
IN OUR FAR WESTERN COUNTIES FOR ANY SPILLAGE INTO THE DVN CWA FOR
LATE IN THE DAY. MID/HIGH LEVEL CLOUDS WILL BE ON THE INCREASE
FROM WEST TO EAST AS WARM AIR ADVECTION KICKS IN. THE THICKENING
CLOUD COVER SHOULD KEEP MAXIMUM TEMPERATURES A BIT BELOW NORMAL...
IN THE MID TO UPPER 70S.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 255 PM CDT THU JUN 13 2013

FRIDAY NIGHT INTO SATURDAY NIGHT LOOKS ACTIVE AGAIN.  THE WESTERN UPPER
TROF IS FORECAST TO MOVE INTO THE PLAINS AND WEAKEN AS IT ENCOUNTERS
RIDGING OVER CENTRAL U.S.   SURFACE HIGH PRESSURE OVER THE GREAT
LAKES FRIDAY EVENING WILL MOVE EAST ALLOWING RETURN FLOW TO DEVELOP
AHEAD OF WEAKENING LOW PRESSURE MOVING OUT OF THE CENTRAL PLAINS.
FRIDAY NIGHT A WARM FRONT SHOULD BE LOCATED OVER SOUTHERN IA OR
NORTHERN MO.  MODELS SHOW H8 FLOW ACROSS THE FRONT INCREASING TO
AROUND 40KTS BY LATE FRIDAY NIGHT INITIALLY POINTED AT WESTERN IA
THEN WITH VEERING FOCUSING MORE TO THE EAST.  CAN/T RULE OUT A
SEVERE THREAT WITH THIS CONVECTION LATE FRIDAY NIGHT...BUT STORMS
SHOULD BE ELEVATED LIMITING THE DAMAGING WIND THREAT. FREEZING
LEVELS ARE PROGGED TO BE AROUND 12KFT WITH FORECAST SOUNDINGS
SHOWING MOIST MID/UPPER LEVELS WHICH SHOULD LIMIT THE LARGE HAIL
THREAT.  PW/S ARE EXPECTED TO BE IN THE 1.5 TO 2 INCH RANGE AND WITH
STORMS MOVING INTO THE UPPER RIDGE AXIS AND SLOWING SO HEAVY RAIN
MAY BE THE BIGGEST THREAT FROM THE OVERNIGHT CONVECTION.  SATURDAY
WITH THE SURFACE BOUNDARY OVER THE AREA AND A WEAK SURFACE WAVE
MOVING ALONG THE BOUNDARY DURING THE AFTERNOON MAY POSE MORE OF A
SEVERE WEATHER RISK.  HOWEVER...A LOT WILL DEPEND ON THE EXTENT OF
THE OVERNIGHT CONVECTION AND ANY PRECIP THAT LINGERS INTO SATURDAY
MORNING.  IF WE GET ENOUGH HEATING SATURDAY THEN DEEP LAYER SHEAR
SHOULD BE STRONG ENOUGH TO SUPPORT SOME SEVERE STORMS DURING THE
AFTERNOON AND EVENING. PRECIP CHANCES WILL BE DIMINISHING SUNDAY AND
IT/S CONCEIVABLE THAT THE AFTERNOON COULD BE DRY AS WEAK S/W RIDGING
SLIDES ACROSS THE FORECAST AREA.  HOWEVER TIMING ISSUES SUPPORT
GOING WITH BROAD BRUSH POPS FOR THE DAY.

MODELS SHOW ANOTHER VIGOROUS S/W AND COLD FRONT MOVING THROUGH EARLY
MONDAY.  WILL CARRY CHANCE POPS FOR THIS FEATURE. MUCH OF THE
REMAINDER OF THE WEEK LOOKS DRY WITH COMFORTABLE TEMPERATURES AND
HUMIDITIES.  NORTHWEST FLOW SET UP OVER THE REGION WITH SURFACE HIGH
PRESSURE MOVING SLOWLY THROUGH THE WESTERN GREAT LAKES REGION. THE
GFS/ECMWF SUGGEST PRECIP CHANCES WILL RETURN TO THE REGION BY THE
END OF THE WEEK AS THE NORTHWEST FLOW BREAKS DOWN.  THE 12Z ECMWF IS
MORE AGGRESSIVE BREAKING DOWN THE PATTERN AND BRINGS THUNDERSTORMS
BACK BY THURSDAY.  THE GFS IS SLOWER...HOLDING PRECIP OFF UNTIL
THURSDAY NIGHT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 642 PM CDT THU JUN 13 2013

GENERALLY VFR CONDITIONS EXPECTED AS SURFACE HIGH PRESSURE SLOWLY
SLIDES EAST OVER THE NEXT 24 HRS. CHANCE OF SHOWERS AND STORMS
WILL RETURN FRIDAY AFTERNOON ESPECIALLY WEST OF THE MISSISSIPPI
RIVER WITH MOISTURE RETURNING ON BACKSIDE OF DEPARTING HIGH AND AN
APPROACHING UPPER LEVEL DISTURBANCE. LIGHT NORTHERLY WINDS WILL
VEER TO NORTHEAST TONIGHT AND THEN SOUTHEAST TO SOUTH ON FRIDAY
WHILE INCREASING TO 10-15 KTS BY FRIDAY AFTERNOON.

&&

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

$$

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