Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 190832
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
332 AM CDT TUE MAY 19 2015

.SYNOPSIS...
ISSUED AT 300 AM CDT TUE MAY 19 2015

ANALYSIS AT 2 AM SHOWS ENTIRE FORECAST REGION UNDER LOW CLOUDS FROM
NEAR RECORD TO RECORD COLD AND STRONG DEPARTING STORM PAST 24-36
HOURS OVER MINNESOTA WHICH IS ROTATING NORTHEAST. DESPITE CLOUDS
AND WINDS OF 15 TO 25 KTS...TEMPERATURES AT 2 AM ARE 40 TO 45 DEGREES
SUPPORTING HOW COLD THE AIR IS FOR MID MAY. UPSTREAM ANALYSIS SHOWS
UPPER LOW IN PACIFIC SOUTHWEST IS EJECTING NORTHEAST WHICH WILL ARRIVE
BASED ON TIMING TOOLS IN AROUND 30 HOURS WITH MAIN FORCING PASSING TO
OUR SOUTH WITH SOUTH 1/2 OR SO OF AREA STILL AT RISK FOR SOME PRECIPITATION.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT TUE MAY 19 2015

SHORT TERM FORECAST CONFIDENCE ASSESSMENT...POOR OR BELOW AVERAGE DUE
TO POOR HANDLING OF COLD AIR AND LOW CLOUDS. THIS HAS IMPACTS ON TEMPERATURES
TODAY AND WHEN CLEARING OCCURS. PERSISTENCE AND TRENDS SUGGEST PARTIAL
CLEARING MID DAY TODAY WITH SOME AREAS IN THE NORTH POSSIBLY STAYING
MOSTLY CLOUDY FOR MOST OF THE DAY. TIMING TRENDS OF SOUTHWEST US SYSTEM
SUGGESTS DECAYING LIGHT RAIN AND SPRINKLES TO ARRIVE IN THE FAR SW AROUND
6 TO 7 AM ON WEDNESDAY.

TODAY...LOWERED MAX TEMPERATURES 1 TO 3 DEGREES WITH RISK SOME AREAS
MAY NEED MAX TEMPERATURES LOWERED FURTHER BY AT LEAST A FEW MORE DEGREES
IF CLEARING IS DELAYED. NORTHWEST WINDS OF 10 TO 20 MPH ARE EXPECTED
TO SLOWLY DECREASE TO 5 TO 10 MPH BY MID AFTERNOON TO MAKE FOR ANOTHER
REMARKABLY COOL DAY.

TONIGHT...INCREASING CLOUDS WITH RISK MINS MAY NEED LOWERING BY ANOTHER
FEW DEGREES...MAYBE 3 PLUS DEGREES MORE IF CLOUDS IN NE ARE DELAYED
WITH UPPER 30S NOT OUT OF THE QUESTION. HAVE INTRODUCED SLIGHT POPS
FAR SW 1/5 AROUND 6 AM AS SW US UPPER DISTURBANCE APPROACHES. WINDS
TO SHIFT TO THE NORTHEAST AT AROUND 5 MPH.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 300 AM CDT TUE MAY 19 2015

FORECAST FOCUS ON RAIN ON WEDNESDAY THEN SHOWERS AND STORMS INCREASE
THIS WEEKEND.

WEDNESDAY...OPERATIONAL MODELS CONTINUE TO INDICATE THE BULK OF THE
RAIN ACROSS MUCH OF OUR SOUTHERN COUNTIES SO HAVE MAINTAINED THE
LIKELY POPS THERE. LESSER COVERAGE IN OUR NORTH AWAY FROM THE BETTER
ISENTROPIC LIFT SO I WILL CONTINUE WITH CHANCE POPS.  MODELS HAVE
LOWERED QPF AMOUNTS WITH THE CONSENSUS RANGING FROM LESS THAN 4
TENTHS OF AN INCH IN THE SOUTH TO LESS THAN A TENTH OF AN INCH ALONG
HIGHWAY 20. INTERESTING THAT THE NAM/ECMWF ACTUALLY HAVE OUR 850 MB
TEMPERATURES NEAR 0C OR SLIGHTLY BELOW BUT THE THICKNESSES ARE TOO
WARM TO SUPPORT ANYTHING BUT RAIN. THIS DOES SHOW YOU HOW COOL IT
WILL BE WITH AFTERNOON HIGHS ONLY IN THE MID 50S DUE TO THE THICK
CLOUD COVER AND RAIN. THE RECORD COOL HIGH AT MOLINE IS 52 SET IN
2002 SO THIS WILL BE CLOSE. THE RAIN SHOULD BE EXITING THE CWA BY
EVENING. WITH SUCH COOL TEMPERATURES CAPE WILL BE NON-EXISTANCE WITH
THE THUNDER THREAT AT ZERO.

THURSDAY THROUGH FRIDAY...CANADIAN HIGH PRESSURE WILL BE IN CONTROL
SO VERY PLEASANT WEATHER IS EXPECTED WITH MAINLY CLEAR SKIES AND
RATHER LIGHT WINDS. MAXIMUM TEMPERATURES ON THURSDAY SHOULD BE IN
THE 60S AND THEN WARMING INTO THE LOWER 70S ON FRIDAY. LOWS WILL BE
MAINLY IN THE 40S.

SATURDAY THROUGH MONDAY...DEEP TROUGH SETTLES INTO THE ROCKIES/PLAINS
WITH A SOUTHWEST FLOW ALOFT IN THE MIDDLE OF THE COUNTRY. THIS SYNOPTIC
PATTERN WILL OPEN UP THE GULF MOISTURE AND WITH A FRONTAL BOUNDARY SOMEWHERE
IN THE REGION THERE WILL BE PERIODS OF SHOWERS AND THUNDERSTORMS...ALONG
WITH DRY PERIODS. THE BIG QUESTION WILL BE HOW FAR NORTH DOES THE WARM
FRONT GET AND IF IT PUSHES NORTH OF THE CWA. IF SO THIS PUTS THE CWA
IN THE WARM SECTOR IN WHICH THE MODELS HAVE BEEN WAY OVERDOING THE
QPF LATELY. FOR NOW THE CONSENSUS IS TO HAVE LIKELY POPS THIS WEEKEND
BUT THIS MAY CHANGE. MAXIMUM TEMPERATURES WILL BE IN THE 70S. DEEP
LAYER SHEAR DOES NOT LOOK IMPRESSIVE SO AS OF NOW THE SEVERE THREAT
APPEARS LOW.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1124 PM CDT MON MAY 18 2015

STRATUS DECK WITH CIGS HOVERING BETWEEN 2500 TO 3500 FT AGL
CONTINUES TO ADVANCE SOUTHWARD ACROSS EASTERN IOWA AND NORTHWEST
ILLINOIS LATE THIS EVENING. CIGS ARE NOW FORECAST TO REMAIN IN THE MVFR
RANGE THROUGH THE NIGHT AT CID AND DBQ...AND POSSIBLY DIP INTO
MVFR IN THE HOURS TOWARD SUNRISE AT MLI...WHILE BRL IS EXPECTED
TO REMAIN ON THE EDGE OF THE DECK AT VFR LEVELS. BRISK...GUSTY NW
WINDS SHOULD GRADUALLY DIMINISH THROUGH THE REST OF TONIGHT.
TUESDAY...THE LOW CLOUDS SHOULD DISSIPATE IN PLACE...WITH ALL
SITES LIKELY TO BE VFR BY LATE MORNING. VFR CONDITIONS ARE THEN
EXPECTED THROUGH THE REST OF THE DAY WITH NORTH WINDS BECOMING
LIGHT IN THE EVENING.

&&

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

&&

$$

SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...HAASE
AVIATION...SHEETS



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