Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 192319
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
619 PM CDT SAT APR 19 2014

.SYNOPSIS...
ISSUED AT 253 PM CDT SAT APR 19 2014

UPPER LOWS OVER ARIZONA AND GEORGIA TODAY...WITH AN UPPER RIDGE
OVER THE LOWER MISSISSIPPI VALLEY. IN THE NORTHERN STREAM...YET
ANOTHER UPPER LOW IN A SERIES OF MANY IS CROSSING MANITOBA. AT THE
SURFACE... RIDGE AXIS STRETCHES FROM THE GREAT LAKES TO THE LA
GULF COAST. RETURN FLOW HAS SET UP OVER THE SOUTHERN PLAINS AND
MIDWESTERN STATES...ALTHOUGH SURFACE RIDGING ALONG THE TX COAST
STILL HAS THE GULF SOMEWHAT CUT OFF.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 253 PM CDT SAT APR 19 2014

NEXT 24 HOURS WILL BRING A QUIET SPRING NIGHT AND BEAUTIFUL EASTER
SUNDAY.  WARM SOUTHERLY RETURN FLOW WILL CONTINUE THROUGH THE
PERIOD...WITH A VERY SLOW INCREASE IN SURFACE DEW POINTS DUE TO LACK
OF DIRECT GULF MOISTURE FEED. WITH CONTINUED SOUTHERLY WINDS
TONIGHT... LOW TEMPS SHOULD ONLY FALL TO AROUND 50.

FOR SUNDAY...CLOUDS WILL INCREASE THROUGH THE DAY AS PIECES OF
ENERGY FROM THE LOW EJECTING OUT OF THE SOUTHWEST US BEGIN TO
APPROACH THE REGION. DUE TO LIMITED MOISTURE...CONVECTION ASSOCIATED
WITH THIS SYSTEM SHOULD BE CONFINED CLOSER TO THE UPPER LOW AND
AREAS OF CONVERGENCE ALONG THE ASSOCIATED SURFACE AND 850 MB
BOUNDARIES...REMAINING WEST AND NORTH OF OUR AREA. THUS...CWFA
GENERALLY EXPECTED TO REMAIN DRY THROUGH THE DAY SUNDAY.  HAVE KEPT
LOW POPS IN THE AFTERNOON IN THE FAR NORTHWEST SECTION NEAR
INDEPENDENCE IN CASE CONVECTION SHOULD DEVELOP IN THE WARM SECTOR
CLOSER TO THE WARM FRONT AND AFFECT THAT AREA BEFORE 00Z/MON.

DMD

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 253 PM CDT SAT APR 19 2014

THE PASSAGE OF AN UPPER LEVEL TROUGH AND SURFACE COLD FRONT WILL
CONCENTRATE THE BEST PRECIPITATION CHANCES ON THE MONDAY PERIOD. A
SURFACE AND UPPER LEVEL RIDGE WILL THEN PROVIDE DRY WEATHER AND NEAR
NORMAL TEMPERATURES TUE AND WED. BEYOND...STILL SOME MODEL
INCONSISTENCIES A WITH LATE WEEK SYSTEM THAT WILL FOCUS A PERIOD OF
RAIN AND THUNDERSTORMS CHANCES AROUND THU AND FRI.

SUNDAY NIGHT INTO MONDAY...HAVE CONTINUED TO CONCENTRATE RAIN
CHANCES ON THE MONDAY FRONTAL PASSAGE. WILL MAINTAIN LOW CHANCE POPS
FOR MAINLY ACROSS THE WEST FOR SHOWERS LATE SUNDAY NIGHT WHERE THERE MAY
BE WEAK FORCING AND MARGINAL ELEVATED INSTABILITY. CLOUD COVER
SHOULD HOLD TEMPERATURES OVERNIGHT IN THE 50S. MONDAY...PASSAGE OF
THE UPPER TROUGH AND SURFACE BOUNDARY SHOULD PROVIDE A PERIOD OF
SHOWERS OVER AND POSSIBLY SOME THUNDERSTORMS FROM LATE MORNING
THROUGH AFTERNOON WHEN DIURNAL INSTABILITY IS MAXIMIZED. THIS
OVERALL LOOKS TO BE A RATHER LIGHT QPF EVENT...IN THE RANGE OF A FEW
TENTHS OF AN INCH. MOS GUIDANCE HIGHS IN THE LOWER TO MID 70S LOOK
TOO OPTIMISTIC GIVEN THE AMOUNT OF MID LEVEL MOISTURE AND RESULTING
CLOUD COVER. WILL CONTINUE TO UNDERCUT WITH HIGHS IN THE UPPER 60S
TO AROUND 70.

TUESDAY INTO WEDNESDAY....HIGH PRESSURE THAT FOLLOWS WILL PROVIDE
MOSTLY CLEAR...DRY AND NEAR TO BELOW NORMAL TEMPERATURES. ON
WEDNESDAY...WARM ADVECTION DEVELOPS AHEAD OF THE NEXT SYSTEM TAKING
SHAPE IN THE PLAINS. OUR FORECAST WILL MAINTAIN LOW CONFIDENCE
CHANCE POPS FOR MAINLY AFTERNOON THUNDERSTORMS AS MODELS TRY TO
DEVELOP CONVECTION ALONG THE RETURNING MOISTURE ADVECTION AND WARM
FRONT. BASED ON THE PAST SEVERAL SYSTEMS...THIS MOISTURE RETURN MAY
BE OVERDONE AND THE DAY MAY TURN OUT TO BE DRY WITH TEMPERATURES
SLIGHTLY WARMER THAN THE ADVERTISED UPPER 50S TO MID 60S.

THURSDAY THROUGH SATURDAY...THERMAL AND MOISTURE ADVECTION ON WHAT
MAY BE A STRONG NOCTURNAL JET SUPPORTS HIGHER CONFIDENCE
THUNDERSTORM CHANCES FOR LATE WEDNESDAY NIGHT. MEDIUM RANGE MODELS
CONTINUE TO DIFFER IN THE TIMING OF THE SURFACE AND UPPER LOW
PROGGED TO ROLL BY TO THE NORTH THU INTO FRIDAY. THE 12Z GFS IS
SLOWER AND DEEPER WITH THIS SYSTEM...WHICH WOULD KEEP RAIN CHANCES
GOING WELL INTO FRIDAY...WHILE THE MORE PROGRESSIVE ECMWF WITH ITS
LOW WELL OVER THE GREAT LAKES BY THIS TIME WOULD INDICATE A DRY AND
BREEZY DAY. EITHER WAY...DEVELOPING UPPER LEVEL DIFFLUENCE AHEAD OF
THIS SYSTEM AND GULF MOISTURE SUPPORTS LIKELY POPS FOR WIDESPREAD
THUNDERSTORMS THURSDAY. SHOWERS AND AT LEAST ISOLATED THUNDERSTORMS
ARE THEN CARRIED OVER INTO FRIDAY LENDING TO THE POSSIBLE SLOWER GFS
TIMING. THE CONSENSUS TRACKING OF THE SURFACE LOW TO THE NORTH
ACROSS MN AND WI WOULD KEEP THE BULK OF THE QPF WELL TO THE
NORTH...BUT THERE COULD STILL BE LIGHT TO MODERATE RAINFALL AMOUNTS
THROUGH THIS PERIOD...DEPENDING ON INTENSITY OF THE CONVECTION
TRIGGERED BY THE SURFACE FRONTAL PASSAGE. THE POSSIBILITY OF THE
MORE PROGRESSIVE ECMWF SOLUTION CONTRIBUTES TO A MENTION OF SHOWERS
ACROSS THE SOUTH CARRIED OVER INTO SATURDAY WHILE A SURGE OF
RELATIVELY COOLER AIR BEHIND THE LATE WEEK SYSTEM CONTINUES NEAR TO
BELOW NORMAL TEMPERATURES.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 616 PM CDT SAT APR 19 2014

A WEAK FRONT WILL REMAIN STALLED FROM EASTERN NE THROUGH NW IA AND
SOUTHEASTERN MN THROUGH LATE SUNDAY AFTERNOON. THIS WILL KEEP
VFR CONDITIONS OVER THE AREA WITH WINDS REMAINING OUT OF THE SOUTH.

&&

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

$$

SYNOPSIS...DMD
SHORT TERM...DMD
LONG TERM...SHEETS
AVIATION...DLF






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