Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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756
FXUS63 KDVN 161227
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
727 AM CDT SAT MAY 16 2015

.SYNOPSIS...
ISSUED AT 335 AM CDT SAT MAY 16 2015

SYNOPSIS...NEARLY STATIONARY FRONTAL BOUNDARY EXTENDED EAST-WEST
ROUGHLY ALONG INTERSTATE 80. SCATTERED SHOWERS HAVE BEEN OCCURING
ALONG AND NORTH OF THE BOUNDARY THE PAST SEVERAL HOURS. THIS IS IN A
ZONE OF WEAK WARM AIR ADVECTION/MOISTURE TRANSPORT BUT DEEP LAYER
SHEAR IS WEAK AND CAPE IS MINIMAL. SOME OF THESE SHOWERS WERE
PRODUCING BRIEF MODERATE TO HEAVY RAIN. CURRENT TEMPERATURES WERE IN
THE LOWER TO MID 60S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CDT SAT MAY 16 2015

FORECAST FOCUS ON SHOWERS AND THUNDERSTORMS CHANCES.

TODAY...MOSTLY CLOUDY SKIES EXPECTED WITH SCATTERED SHOWERS THIS
MORNING ACROSS OUR NORTHERN CWA...ALONG AND NORTH OF A FRONTAL
BOUNDARY THAT WILL BE LIFTING NORTHWARD TODAY. THE BETTER COVERAGE
WILL BE ASSOCIATED WITH THE FRONT WITH ONLY ISOLATED SHOWERS
POSSIBLE TO THE SOUTH. DEEP LAYER SHEAR AND CAPE IS MINIMAL THIS
MORNING SO WILL NOT MENTION THUNDER IN THE GRIDS...BUT THERE COULD
BE AN ISOLATED BRIEF LIGHTNING STRIKE. THIS AFTERNOON WITH SOME
PARTIAL SUNSHINE SHOULD PUSH SBCAPES TO ABOUT 1500 J/KG BUT SHEAR
AGAIN IS WEAK. WITH THE FRONT PUSHING NORTHWARD OUT OF THE DVN CWA
THERE WILL NOT BE MUCH OF A FOCUS FOR ORGANIZED CONVECTION.
INSTEAD I EXPECT ISOLATED TO SCATTERED SHOWERS AND A FEW RANDOM
STORMS TO DEVELOP THIS AFTERNOON WITH THE BETTER INSTABILITY. WITH
A LOT OF CLOUD COVER EXPECTED THIS SHOULD KEEP MAXIMUM
TEMPERATURES MAINLY IN THE UPPER 70S...WITH SOME SPOTS ABOUT 80.

TONIGHT...I HAVE MAINTAINED SMALL POPS AS THE BETTER FORCING SHIFTS
WELL TO OUR WEST AHEAD OF A DEEPENING CYCLONE IN THE CENTRAL PLAINS.
MUCH OF THE NIGHT IN THE DVN CWA COULD ACTUALLY END UP DRY WITH
THUNDERSTORM CHANCES ARRIVING LATE TONIGHT IN OUR WESTERN CWA. THESE
STORMS WOULD BE IN A WEAKENING FASHION FROM MORE VIGOROUS ACTIVITY
IN THE PLAINS. LOWS WILL BE IN THE MID 60S AT MOST LOCATIONS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 335 AM CDT SAT MAY 16 2015

LIGHT TO MODERATE RAINFALL FROM SHOWERS AND THUNDERSTORMS THIS WEEKEND...THEN
MOSTLY DRY AND MAINLY BELOW NORMAL TEMPERATURES THE REST OF NEXT WEEK.

LONG TERM FORECAST CONFIDENCE ASSESSMENT...GOOD OR SLIGHTLY ABOVE AVERAGE
WITH TIMING AND STRENGTH OF FRONTAL PASSAGE SUNDAY MAIN ISSUE WITH TRENDS
FOR A WEAKER SYSTEM WITH LESS PRECIPITATION AND SEVERE RISK. HIGH TEMPERATURES
MAY BE A CATEGORY TOO COOL WITH SURFACE CANADIAN HIGH AND MINS POSSIBLY
A FEW DEGREES TOO MILD WITH LIGHT WINDS WITH RISK OF PATCHY FROST NOT
OUT OF THE QUESTION TUESDAY AND/OR WEDNESDAY AM.

OVERVIEW...INITIALIZATION AND VERIFICATION AND RUN TO RUN VARIANCE SUPPORTS
A 60/40 MIX OF HI-RES ECMWF AND GFS/GEM-NH. TRENDS ARE FOR SLOWER FRONT
SUNDAY WITH DELAYED CAA INTO MONDAY. ZONAL FLOW PATTERN SUGGEST ANY
PRECIPITATION AMOUNTS TO BE LIGHT MID WEEK IF AT ALL.

SUNDAY...BREEZY AND WARM WITH SCATTERED CONVECTION. LOWERED POPS BY
10 TO 15 PERCENT WITH LIKELY TO HIGH CHANCE POPS DUE TO EJECTING UPPER
LOW IS FILLING WITH LESS COHERENT SURFACE FRONT FOR LESS FORCING. COULD
SEE WITH DEEP MIXING SOME HIGHS IN THE MID 80S FOR LATER SHIFTS TO ASSESS.
RISK OF SEVERE IS QUITE MARGINAL DUE TO FORCING ISSUES AND TIMING MOSTLY
EARLY TO MID DAY AT THIS TIME. SUNDAY NIGHT...ANY LINGER PRECIPITATION
SHOULD END BY MID EVENING WITH CLEARING SKIES AND RAISED MINS TO LOW
50S NW TO AROUND 60F FAR SE DUE TO SLOWER FILTRATION OF COOL AIR. POPS
BASED ON TRENDS MAY STILL BE TOO HIGH BY AT LEAST 10 PERCENT MOST LOCATIONS.

MONDAY...RAISED TEMPERATURES A FEW DEGREES AGAIN DUE TO DELAYED COOLING
WITH A FEW MORE DEGREES WARMING POSSIBLE FOR LATER SHIFTS TO CONSIDER
AND FAIR. MONDAY NIGHT...COOL AND CRISP WITH QUESTION OF HIGH LIGHT
WINDS BECOME FOR LOWS WITH UPPER 30S SUGGESTED FAR NW SECTIONS IF WINDS
DECOUPLE AND LOWER TO MIDDLE 40S ELSEWHERE.

TUESDAY...COOL AND COMFORTABLE WITH POSSIBLE HIGHS MOST LOCATIONS ARE
A FEW DEGREES TOO COOL DUE TO GOOD BL MIXING. TUESDAY NIGHT...MAY BE
THE BEST CHANCE FOR FROST IN THE NORTH WITH LOCAL TECHNIQUES SUGGESTING
RISK OF PATCHY FROST ALONG AND NORTH OF HIGHWAY 30 IF CLOUDS DO NOT
COME IN AS FAST AS FORECAST. SHOULD HAVE BETTER IDEA ON THIS RISK THE
NEXT 24 HOURS.

WEDNESDAY AND THURSDAY...MOSTLY CLOUDY IN GENERAL AND COOL WITH HIGHS
IMPACTED BY CLOUD COVERAGE. LIGHT SHOWERS MAY BE POSSIBLE IN THE SOUTH
1/2 OR SO OF THE FORECAST REGION. ANY RAIN AMOUNTS AT THIS TIME WITH
SURFACE HIGH NEARBY AND ELEVATED WEAK FORCING SHOULD BE A TENTH OF AN
INCH OR LESS. LOWS THURSDAY AM SHOULD BE IN THE MIDDLE TO UPPER 40S
MOST LOCATIONS.

FRIDAY AND SATURDAY...NEAR NORMAL TEMPERATURES WITH CHANCE OF RAIN
POSSIBLE IN FORM OF SHOWERS AND STORMS ON SATURDAY WITH POOR CONFIDENCE
ON TIMING WITH JET STRUCTURE SUPPORTING RAIN ISSUES MAY BE DELAYED
BY 12 TO 24 HOURS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 724 AM CDT SAT MAY 16 2015

IFR CONDS TIL 17Z/16 THEN VFR CONDS THIS AFTERNOON AND EVENING
THEN MVFR CIGS/VIS TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS
TODAY AND TONIGHT. SOUTH WINDS AROUND 10 KNOTS THROUGH THE PERIOD.

&&

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

$$

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



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