Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 232157
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
357 PM CST FRI JAN 23 2015

.SYNOPSIS...
ISSUED AT 345 PM CST FRI JAN 23 2015

MID/HIGH CLOUDS WERE OVER MOST OF THE DVN CWA THIS AFTERNOON WITH
3 PM TEMPERATURES IN THE 30S TO LOWER 40S. ELSEWHERE...READINGS WERE
IN THE MID 40S TO MID 50S ACROSS MUCH OF THE GREAT PLAINS.

A SURFACE TROUGH EXTENDED FROM NORTHERN MN TO WESTERN KS MOVING
SOUTHEAST. SATELLITE LOOPS INDICATE AN AREA OF LOW STRATUS IN NORTHERN
MN BUT THIS WAS MOVING SOUTHEAST INTO NW WI.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CST FRI JAN 23 2015

FORECAST FOCUS ON CLOUDS AND MILD TEMPERATURES.

TONIGHT...MID/HIGH CLOUDS WILL PUSH SOUTHEAST ACROSS THE CWA THIS
EVENING FOLLOWED BY CLEAR TO PARTLY CLOUDY SKIES. A SURFACE TROUGH
WILL ALSO PUSH SOUTHEAST ACROSS THE CWA AFTER MIDNIGHT TURNING
WINDS TO THE NORTHWEST. I AM REALLY STRUGGLING TO FIND THE REASON WHY
STRATUS WOULD DEVELOP IN THIS DRY AIRMASS THAT THE GUIDANCE IS
TRYING TO DEPICT. FOR NOW BELIEVE THE MODELS ARE WAY OVERDOING THE
LOW LEVEL MOISTURE AND WILL DISREGARD THE FORECAST OF LOW STRATUS.
MINIMUM TEMPERATURES WILL BE IN THE MID TO UPPER 20S.

SATURDAY...ENJOY THE DAY AS WESTERLY WINDS PULL MILD AIR INTO THE
CWA AHEAD OF THE STRENGTHENING ALBERTA CLIPPER THAT WILL BE DIVING
INTO THE NORTHERN PLAINS. WE SHOULD START OUT SUNNY WITH MID/HIGH
LEVEL CLOUDS INCREASING AHEAD OF THE CLIPPER...ESPECIALLY DURING
THE AFTERNOON. MAXIMUM TEMPERATURES WILL RANGE FROM THE UPPER 30S
NORTH TO MID 40S SOUTH.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 345 PM CST FRI JAN 23 2015

SATURDAY NIGHT AND SUNDAY...CONFIDENCE IS HIGH THAT A CLIPPER SYSTEM
WILL IMPACT THE CWA DURING THIS TIMEFRAME. HOWEVER... CONFIDENCE
IS LOW... TO MODERATE AT BEST WITH REGARDS TO TRACK AND STRENGTH OF
SYSTEM AND PCPN AMOUNTS/TYPE. OVERALL... MOST SOLUTIONS CONTINUE
TO SHIFT THE TRACK OF THE SYSTEM FURTHER SOUTH/WEST AND GIVEN THE
NAM AND GEM TRENDING MORE SOUTHERLY AND WITH SYSTEM DIGGING INTO THE
LONGWAVE TROUGH I AM LEANING TOWARD MORE SOUTHERLY TRACK AND OPTED
FOR BLEND OF GFS...ECMWF AND UKMET MODELS WITH TRACK OF COMPACT
VIGOROUS SHORTWAVE AND ATTENDANT SURFACE LOW... WITH TRACK OF THE
SURFACE LOW NEAR TO JUST SOUTH OF QUAD CITIES ON SUNDAY. TRACK THOUGH
IS ANYTHING BUT CERTAIN AND LIKELY TO SHIFT A BIT MORE AS WE BETTER
SAMPLE OVER THE NEXT 12-18 HRS THE IMPRESSIVE SYSTEM ON SATELLITE
IMAGERY APPROACHING THE NORTHERN BRITISH COLUMBIA COASTLINE. WITH THE
SYSTEM DIGGING AND STRENGTHENING... AND WITH SHARPENING NORTHWEST
FLOW ALOFT THE FEELING IS IF ANY MORE SHIFT WOULD LIKELY BE A BIT MORE
SOUTH/WEST. WITH THE TREND MORE SOUTH/WEST IT ALLOWS FOR MORE COLD
AIR AND HENCE MORE IN THE WAY OF SNOW... AND AS SUCH THE FORECAST HAS
BEEN ADJUSTED TO TREND IN THAT DIRECTION. THE HIGHEST PCPN CHANCES
AND BEST POTENTIAL FOR ACCUMULATING SNOW WOULD BE FOUND TO THE NORTH
OR LEFT OF THE SURFACE LOW TRACK AND WITH A LOW TRACKING NEAR/SOUTH
OF QUAD CITIES WOULD FAVOR NORTHERN 1/2 TO POSSIBLY 2/3RDS OF CWA BUT
DEPENDING ON TRACK. PRECIPITABLE WATER VALUES AND STRENGTHENING SYSTEM
WOULD SUPPORT LIQUID QPF AMOUNTS OF AROUND 0.2 TO 0.4 INCH WITHIN THE
AXIS OF MAIN FORCING WHICH DEPENDENT ON TRACK. SNOW TO LIQUID RATIOS
OF 10-13:1 WITH SURFACE TEMPS AROUND OR EVEN ABOVE FREEZING SUPPORT
A HEAVIER AND WET SNOW WITH POSSIBILITY OF 2-5 INCH SNOW ACCUMS
WITHIN THE AXIS OF MAIN FORCING AND HIGHER QPF WHICH ATTIM BASED ON
BLEND OF GFS/ECMWF/UKMET IS FAVORING 30 MILES +/- LINE FROM VINTON IA...
TO CLINTON IA... TO PRINCETON IL. ALIGNMENT OF STRONG LIFT IN THE
DENDRITIC GROWTH ZONE SUPPORTS PERIOD OF DECENT SNOW RATES (1+ INCH/HR)
POTENTIAL WITHIN THIS BAND OVERNIGHT SAT NGT INTO SUNDAY AM WITH LOW
POTENTIAL FOR EVEN A RUMBLE OR TWO OF THUNDER BASED ON LOW/MID LEVEL
THETA-E LAPSE RATES NEARING 0 K/KM. THIS RATE OF SNOWFALL WOULD EASILY
BE ABLE TO OVERWHELM THE NEAR TO ABOVE FREEZING SURFACE TEMPS FOR AT LEAST
A WET...SLUSHY ACCUM AND DEVELOPING NORTHEAST WINDS DURING HEAVIEST PCPN
WOULD ALSO AID IN TEMPS FALLING BACK TO FREEZING OR A BIT COLDER ASSISTING
GROUND ACCUM.

SO THE BOTTOM LINE IS CLIPPER SYSTEM WILL AFFECT THE CWA LATER SAT NIGHT
AND SUNDAY WITH RAIN AND SNOW. CONFIDENCE IS HIGH ON THIS. CONFIDENCE
REMAINS LOW ON TRACK AND LOCATION/AMOUNTS OF PCPN AND PCPN TYPE. AT
THIS TIME IT IS LOOKING LIKE SNOW WITH ACCUMULATIONS ROUGHLY NORTH 1/2
OF CWA OR SO WITH RAIN OR RAIN/SNOW MIX TO THE SOUTH... BUT THIS AGAIN WILL
BE DEPENDENT ON THE TRACK AND NO DOUBT LIKELY TO CHANGE SO STAY TUNED !

MONDAY-FRIDAY... CWA LOOKS TO RESIDE IN A FAIRLY ACTIVE PATTERN SITUATED
MAINLY IN THE BAROCLINIC ZONE BETWEEN WESTERN RIDGE AND WARMTH... AND
EASTERN TROUGH AND COLD. THIS THERMAL GRADIENT WILL ACT AS THE PATH FOR
SEVERAL CLIPPER SYSTEMS ABOUT EVERY 24-48 HRS WITH ROUGH TIMING OF
MONDAY... WEDNESDAY AND FRIDAY WITH INITIAL SYSTEM LIGHT SNOW MONDAY
THEN POTENTIAL FOR MIX WITH MID TO LATE WEEK SYSTEMS AS MORE WARMTH IS
ENTRAINED IN DOWNSLOPE ENVIROMENT TO OUR WEST. EXPECT TEMP SWINGS DURING
THE PERIOD WITH TEMPS MAINLY NEAR TO ABOVE NORMAL. SYSTEM LATE WEEK LOOKS
TO USHER IN MUCH COLDER AIR TO END JANUARY AND BEGIN FEBRUARY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 345 PM CST FRI JAN 23 2015

VFR CONDS THROUGH THIS TAF CYCLE. A SURFACE TROUGH WILL PUSH
SOUTHEAST ACROSS THE TAF SITES AFTER 06Z/24. SOUTH TO SOUTHWEST
WINDS 10 TO 15 KNOTS REMAINDER OF THIS AFTERNOON AND EVENING THEN
NORTHWEST AROUND 10 KNOTS OR LESS LATER TONIGHT BEHIND THE TROUGH.
WINDS BECOMING WEST ON SATURDAY.

&&

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

$$

SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...05
AVIATION...HAASE





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