Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 012356
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
656 PM CDT WED APR 1 2015

.UPDATE...
ISSUED AT 656 PM CDT WED APR 1 2015

BASED ON OBSERVATION TRENDS OVER THE PAST SEVERAL HOURS...HAVE
UPDATED FOR WARMER HOURLY TEMPERATURES THIS EVENING...LOWER
DEWPOINTS/RELATIVE HUMIDITY...AND STRONGER WINDS. MODELS CONTINUE
TO BE OVERDONE WITH THE LOW LEVEL MOISTURE...AND RH VALUES WILL
REMAIN LOW OVER THE NEXT SEVERAL HOURS.

MORE DETAILS INCLUDED IN THE FIRE WEATHER DISCUSSION.

&&

.SYNOPSIS...
ISSUED AT 339 PM CDT WED APR 1 2015

STRONG SOUTHERLY WINDS HAVE DEVELOPED ACROSS THE MIDWEST
TO THE SOUTH OF A 994 MB LOW LOCATED ON THE NORTH DAKOTA/MINNESOTA
BORDER. CLEAR SKIES AND RELATIVELY DEEP BOUNDARY LAYER MIXING IN A
DRY ENVIRONMENT HAS PUSHED SFC TEMPS INTO THE 70S AND EVEN LOWER 80S
WHICH HAS PRODUCED EXTREME FIRE WEATHER CONDITIONS ACROSS MUCH OF
EASTERN IOWA AND PORTIONS OF WESTERN ILLINOIS.

MOLINE IS CURRENTLY AT 80F/32F WITH RH DOWN TO 17 PERCENT AND WINDS
GUSTING NEAR 30 MPH. IMPRESSIVELY DRY FOR THIS PART OF THE COUNTRY.
IN FACT SEVERAL SMOKE PLUMES HAVE BEEN DETECTED ON RADAR AS OF 3 PM.

A RED FLAG WARNING IS IN EFFECT FOR MOST OF EASTERN IOWA AND A
PORTION OF FAR WEST-CENTRAL ILLINOIS UNTIL 7 PM CDT WHERE WINDS ARE
GUSTING NEAR 30 MPH AND RH IS NEAR 20 PERCENT. OUTSIDE OF THIS ZONE
CONDITIONS ARE NOT QUITE AS BAD BUT ELEVATED FIRE WEATHER CONDITIONS
STILL EXIST. IF A GRASS FIRE OR WILDFIRE WERE TO DEVELOP IT WOULD
SPREAD RAPIDLY.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 339 PM CDT WED APR 1 2015

THIS EVENING AND TONIGHT...THE FIRE DANGER WILL GRADUALLY DECREASE
THROUGH THE EVENING HOURS...AFTER 7 PM...AS WINDS SLOWLY SUBSIDE
AND RELATIVE HUMIDITY INCREASES.

AN APPROACHING COLD FRONT WILL SPREAD SHOWERS AND THUNDERSTORMS INTO
THE AREA...MOSTLY BETWEEN 3AM-9AM/THU. MUCAPE IS FORECAST TO REACH
TO NEAR 1000 J/KG WITH 0-6 KM BULK SHEAR AROUND 30 KTS. A FEW STRONG
STORMS ARE POSSIBLE WITH THE MAIN THREAT BEING WIND GUSTS OVER 40
MPH. NIGHTTIME STABILIZATION WILL LIMIT THE OVERALL THREAT.

AS PWATS INCREASE TO 1.00-1.25 INCHES CONFIDENCE FOR WIDESPREAD
RAINFALL AMOUNTS AROUND 0.25 INCHES WILL INCREASE. AREAS THAT
RECEIVE THE STRONGEST THUNDERSTORMS MAY SEE UP TO 0.50 INCHES.

THURSDAY...SFC LOW PRESSURE TROUGH WILL BE MOVING EAST OF THE AREA.
ANY RESIDUAL SHOWER ACTIVITY SHOULD EXIT THE EASTERN CWA BY THE LATE
MORNING/EARLY AFTN. STEADY NW FLOW WILL CAUSE DEWPOINTS TO
CONTINUALLY FALL AND RELATIVE HUMIDITY TO DECREASE THROUGH THE DAY.
OVERALL A PLEASANT AFTN IS FORECAST WITH HIGHS IN THE 60S.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 339 PM CDT WED APR 1 2015

AN ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH LATE THIS WEEK
AND INTO NEXT WEEK WITH SEVERAL CHANCES FOR RAIN. TEMPERATURES
WILL SWING FROM ABOVE NORMAL TO A LITTLE BELOW NORMAL.

THURSDAY EVENING AND THURSDAY NIGHT...DRY CONDITIONS WILL BE SEEN
THURSDAY EVENING AS THE FRONT MOVES FURTHER SOUTH AND EAST OF THE
AREA. AFTER MIDNIGHT...A NEW ROUND OF MOISTURE AND FORCING BEGINS
MOVING INTO THE AREA. HOWEVER... ATMOSPHERIC PROFILES SHOW THE
ATMOSPHERE EXTREMELY DRY BELOW 7000 FEET. THUS IF PRECIPITATION
WOULD REACH THE GROUND IT WOULD BE VERY LIGHT. THE MOST LIKELY
AREA FOR ANY VERY LIGHT RAIN/SPRINKLES IS SOUTH OF A KOTM TO KGBG
LINE.

ON FRIDAY...FORCING AND MOISTURE MOVE ACROSS THE AREA DURING THE
MORNING. LIGHT RAIN WILL OVERSPREAD THE SOUTHEAST TWO THIRDS TO
THREE QUARTERS OF THE AREA BUT RAINFALL AMOUNTS WILL BE LIGHT.

IN LOOKING AT THERMAL PROFILES OF THE ATMOSPHERE...THERE IS A STRONG
POTENTIAL FOR COOLING OF THE ATMOSPHERIC COLUMN. THUS TEMPERATURES
MAY ACTUALLY FALL WHEN THE RAIN BEGINS ON FRIDAY. ADDITIONALLY...IT
IS WITHIN THE REALM OF POSSIBILITY THAT A RAIN/SNOW MIX MIGHT
DEVELOP IN THE STRONGEST FORCING FRIDAY MORNING. IF THIS OCCURS...
THE MOST LIKELY AREA WOULD BE SOUTH OF AN KOTM TO KVYS LINE.

THE RAIN WILL END FROM WEST TO EAST FRIDAY AFTERNOON WHICH SHOULD
ALLOW TEMPERATURES TO CLIMB. HOWEVER...HIGH TEMPERATURES WILL BE
BELOW NORMAL.

FRIDAY NIGHT/SATURDAY QUIET AND DRY CONDITIONS WILL BE SEEN AS HIGH
PRESSURE MOVES THROUGH THE MIDWEST. TEMPERATURES SHOULD BE CLOSE TO
NORMAL.

SATURDAY NIGHT ON...A WEAK STORM SYSTEM WILL MOVE THROUGH THE
UPPER MIDWEST SATURDAY NIGHT INTO SUNDAY. THE BETTER
FORCING/MOISTURE REMAINS ACROSS MINNESOTA AND WISCONSIN. THE MODEL
CONSENSUS HAS SLIGHT CHANCE POPS NORTH OF HIGHWAY 30 WITH THE BEST
CHANCES IN THE HIGHWAY 20 CORRIDOR EAST OF DUBUQUE. THE
PRECIPITATION SHOULD BE A COLD RAIN BUT A MIX MAY DEVELOP IN THE
HIGHWAY 20 CORRIDOR EAST OF DUBUQUE SATURDAY NIGHT.

THE ACTIVE WEATHER PATTERN WILL CONTINUE INTO NEXT WEEK WITH SEVERAL
STORM SYSTEMS POSSIBLE. HOWEVER...THE MODELS DISAGREE ON WHERE THE
STORMS WILL TRACK AND THE TIMING OF THE INDIVIDUAL STORM SYSTEMS.

AS A RESULT...THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS SUNDAY
NIGHT. THE CONSENSUS HAS CHANCE POPS MONDAY THROUGH TUESDAY NIGHT.
ON WEDNESDAY...THE MODEL CONSENSUS HAS SLIGHT CHANCE TO LOW CHANCE
POPS FOR THE AREA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 656 PM CDT WED APR 1 2015

STRONG AND GUSTY SOUTH WINDS AHEAD OF A COLD FRONT ADVANCING FROM
THE MO RIVER VALLEY WILL CONTINUE THIS EVENING. THUNDERSTORMS
OCCURRING ALONG AND BEHIND THIS FRONT WILL NOT LIKELY IMPACT THE
TERMINALS UNTIL THE 09Z TO 12Z TIMEFRAME. THE ONSET TIME AND
POTENTIAL FOR THUNDERSTORMS IS LOW CONFIDENCE AT THIS TIME...WHICH
HAS BEEN DEMONSTRATED WITH A WINDOW OF TEMPO OR PROB30 GROUPS.
MORE WIDESPREAD SHOWERS...AND THE ONSET OF MVFR CONDITIONS WAS
DELAYED TO AROUND 12Z TO 16Z. WITH FORECAST MODELS TRENDING TOO
HIGH WITH LOW LEVEL MOISTURE...HAVE OPTED FOR A MORE OPTIMISTIC
CIG FORECAST TO ACCOMPANY THE RAIN...IGNORING THE IFR CONDITIONS
MODELS CURRENTLY ADVERTISE. WINDS WILL DIMINISH AND VEER TO THE
WEST AND THEN NORTHWEST WITH THE PASSING FRONT THURSDAY MORNING
WITH CONDITIONS IMPROVING TO VFR.

&&

.FIRE WEATHER...
ISSUED AT 656 PM CDT WED APR 1 2015

AS OF 6 PM...SURFACE WINDS WERE HOLDING AT 20 TO 30 MPH SUSTAINED
WITH GUSTS AS HIGH AS 40 MPH. AT THE SAME TIME...DEWPOINTS WERE
RUNNING IN THE 30S...WITH NEAR 40 APPROACHING FAR NE MO AND SE IA.
THIS WAS KEEPING RH VALUES IN THE 20 TO 30 PERCENT RANGE...
RESULTING IN GDFI VALUES VERY HIGH TO EXTREME ACROSS EASTERN IA.

WINDS WILL REMAIN STRONG EARLY THIS EVENING IN THE DEEP MIXING AND TIGHT
SURFACE PRESSURE GRADIENT AHEAD OF A COLD FRONT APPROACHING THE
MO RIVER VALLEY. CURRENT TIMING SUGGESTS THIS FRONT WILL NOT
LIKELY REACH EASTERN IA TO BRING IN APPRECIABLE RAIN AND
THUNDERSTORM CHANCES UNTIL AFTER MIDNIGHT. THERE IS A LOW
POTENTIAL THAT SOME HIGH BASED STORMS COULD DEVELOP OR MOVE INTO
SE IA AND W CENTRAL IL LATE THIS EVENING.

HIGHER DEWPOINTS ADVECTING INTO THE AREA FROM MO...COMBINED WITH
FALLING TEMPERATURES THIS EVENING WILL LEAD TO RH VALUES RECOVERING
BACK INTO AT LEAST THE 40 TO 50 PERCENT RANGE BY 9 PM.
THIS...ALONG WITH WINDS DIMINISHING TO 15 TO 25 MPH IS EXPECTED TO
RETURN GFDI VALUES TO THE HIGH RANGE BY THEN. IN THE MEAN
TIME...VERY HIGH TO NEAR EXTREME VALUES WILL CONTINUE EARLY THIS
EVENING. WILL ALLOW THE RED FLAG WARNING TO EXPIRE AT 7 PM...BUT
ADVISE OF THE ON-GOING CRITICAL FIRE WEATHER CONDITIONS THROUGH
SPECIAL WEATHER STATEMENTS.

&&

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

&&

$$

UPDATE...SHEETS
SYNOPSIS...UTTECH
SHORT TERM...UTTECH
LONG TERM...08
AVIATION...SHEETS
FIRE WEATHER...SHEETS






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