Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 161725
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1225 PM CDT THU APR 16 2015

.SYNOPSIS...
ISSUED AT 246 AM CDT THU APR 16 2015

REGION STUCK BETWEEN SYSTEMS WITH UPPER LOW NEAR NEW MEXICO SPAWNING
AREAS OF MOSTLY MID AND HIGH CLOUDS ACROSS THE REGION. WEAK HIGH PRESSURE
OVER LAKE MICHIGAN TO KEEP LIGHT WINDS TODAY AND UPPER AIR ANALYSIS
SHOWS UPPER LOW NEARLY STATIONERY SUGGESTING NO IMPACTS TO OUR AREA
FOR AT LEAST ANOTHER 24 HOURS. NEAR NEUTRAL THERMAL ADVECTION TO SUGGEST
PERSISTENCE A GOOD STARTING POINT TODAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 246 AM CDT THU APR 16 2015

SHORT TERM FORECAST CONFIDENCE...GOOD OR ABOVE AVERAGE WITH MAIN ISSUES
AMOUNT OF CLOUDS TODAY AND IMPACTS ON TEMPERATURES. TRENDS SUGGEST DOWNWARD
MOTION MAY ALLOW A BIT MORE SUNSHINE TO PARTLY SUNNY SKIES AND FOR HIGHS
TO RISE TO SLIGHTLY ABOVE HIGHER END GUIDANCE. CLOUD IMPACTS TONIGHT
MAY BE OVERDONE AND SUGGEST POSSIBLY LOWER MINS ON SOME AREAS.

TODAY...PARTY SUNNY WITH HIGHS WITHIN A COUPLE OF DEGREES OF YESTERDAY/S
HIGHS. THIS WOULD BE MOSTLY IN THE 68 TO 74 DEGREE RANGE...OR 8 PLUS
DEGREES ABOVE NORMAL. WINDS EAST TO NORTHEAST AT 4 TO 8 MPH AND DEWPOINTS
ABOUT 5 TO 8 DEGREES HIGHER THAN YESTERDAY BUT STILL QUITE LOW WITH
RH VALUES GENERALLY BELOW 50 PERCENT MOST OF THE DAY.

TONIGHT...PARTLY CLOUDY WITH INTERVALS OF CLEARING POSSIBLE AND LIGHT
WINDS MAY ALLOW FOR LOWER MINS AND POSSIBLY PATCHY FOG FOR LATER SHIFTS.
CURRENTLY GOING WITH UPPER 40S TO LOWER 50S WHICH WOULD BE AROUND 10
DEGREES WARMER THAN NORMAL.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 246 AM CDT THU APR 16 2015

FRIDAY...ZONAL MID-LEVEL WINDS WILL PREVAIL DOWNSTREAM OF A CUT-OFF
LOW OVER THE FOUR CORNERS. WITH 1000-500MB THICKNESSES NEAR 558 DAM
AND PARTLY SUNNY SKIES IT WILL BE A WARM DAY IN THE MID/UPPER
70S...ABOUT 15 DEGREES ABOVE AVG. THERE IS A VERY SLIGHT CHANCE FOR
SHOWERS AT NIGHT ACROSS THE FAR WESTERN CWA.

SATURDAY AND SUNDAY...CONFIDENCE IS INCREASING FOR A WIDESPREAD RAIN
EVENT SAT NIGHT INTO SUN. MODELS IN GENERAL AGREEMENT ON DROPPING AN
ALBERTA CLIPPER DOWN TO NORTH DAKOTA BY SUN AND PULLING THE CUT-OFF
LOW NORTHEASTWARD TOWARD WESTERN GREAT LAKES. AT THE SFC...THE
MODELS FORM AN ELONGATED TROUGH/DUAL-LOW STRUCTURE WHICH WILL
STRETCH FROM SOUTHERN MANITOBA ALL THE WAY DOWN TO ARKANSAS. ONE SFC
LOW IS FORECAST TO TRACK ACROSS N MINNESOTA INTO W ONTARIO AND
ANOTHER ACROSS N ILLINOIS. THE MODELS HAVE TRENDED THE TRACK OF THE
SOUTHERN LOW TOWARD THE WEST WHICH WOULD INCREASE CHANCES FOR
MODERATE RAINFALL AMOUNTS ACROSS E IOWA/W ILLINOIS/NE MISSOURI.

300MB WINDS ARE FORECAST TO BECOME SOUTHERLY SAT NIGHT/SUN WHICH IS
A TESTAMENT TO THE DEGREE OF TROUGH AMPLIFICATION AND DEEP
TROPOSPHERIC WV TRANSPORT. THIS TYPE OF KINEMATIC REGIME IS OFTEN
ASSOCIATED WITH WIDESPREAD PRECIP ASSUMING OTHER INGREDIENTS ARE
PRESENT. CURVATURE IN THE FLOW AND EMBEDDED JET STREAKS SHOULD
PROVIDE ASCENT NECESSARY FOR A BAND OF RAIN AND ISOLATED
THUNDERSTORMS. LOW TO MIDDLE TROPOSPHERIC MOISTURE ADVECTION
IS FOCUSED MORE ON SAT NIGHT THAN SUN MORNING...BUT A SECONDARY
VORT. MAX MAY BRING ADDITIONAL SHOWERS SUN EVENING/NIGHT.

MOISTURE POTENTIAL...AMOUNTS ARE TRICKY THIS FAR OUT BUT LIGHT TO
MODERATE AMOUNTS LOOK LIKELY. THE NAEFS IS PROJECTING PWAT VALUES
ABOUT 1-1.5 STANDARD DEVIATIONS ABOVE THE MEAN FOR THE MIDDLE OF
APRIL. MORE SPECIFICALLY...THE GFS HAS PWAT VALUES PEAKING BETWEEN
1-1.25 INCHES. THE GFS AND ECMWF BOTH HAVE SFC DEWPOINTS IN THE 50S.

MONDAY AND TUESDAY...MUCH COOLER PATTERN IS EXPECTED AS LARGE SFC
LOW OCCLUDES AND REMAINS NEARLY STATIONARY OVER ONTARIO. HIGHS WILL
BE IN THE 50S WITH BREEZY WESTERLY WINDS.

BOTH THE GFS AND ECMWF HAVE 850MB TEMPS NEAR -4C AND 1000-500MB
THICKNESS HOVERING NEAR 534 DAM. HOW TEMPS EXACTLY PLAY OUT WILL BE
DEPENDENT ON EXTENT/THICKNESS OF CLOUD COVER. DRY WEATHER IS
ANTICIPATED AT THIS TIME.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1222 PM CDT THU APR 16 2015


VFR CONDITIONS WILL BE SEEN THROUGH 06Z/17 AS ANOTHER HIGH
PRESSURE MOVES INTO THE GREAT LAKES. AFT 06Z/17 THE POSSIBILITY
DOES EXIST FOR SOME MVFR VSBYS DUE TO HIGHER MOISTURE LEVELS IN
THE LOWER ATMOSPHERE. IF MVFR CONDITIONS DEVELOP...CONDITIONS WILL
IMPROVE TO VFR AFT 12Z/17.

&&

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

$$

SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...UTTECH
AVIATION...08





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