000
FXUS63 KDVN 052109
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
309 PM CST SUN FEB 5 2012

.SYNOPSIS...
STRATUS HAS BEEN THE MAIN FOCUS OF THE DAY...WITH STRATUS EXTENDING
FROM SOUTHEAST MINNESOTA AND WESTERN WISCONSIN...NEARLY ALL OF
IOWA...AND EXTENDING BACK INTO EASTERN NEBRASKA.  IT HAS MAINLY
AFFECTED THE WESTERN HALF OF THE FORECAST AREA...WITH AREAS ALONG
AND EAST OF THE MISSISSIPPI RIVER MOSTLY IN THE CLEAR.  THIS STRATUS
IS TRAPPED UNDER A STRONG SURFACE HIGH PRESSURE WHICH IS CENTERED
OVER KANSAS....WITH A BROAD RIDGE EXTENDING NORTHEAST UP OVER IOWA
AND EXTENDING UP INTO WISCONSIN.  SOUNDINGS FROM THIS MORNING...
AIRCRAFT REPORTS AND AIRCRAFT SOUNDINGS FROM THE AREA TODAY INDICATE
THAT WE HAVE A SATURATED LAYER AROUND 950MB...GENERALLY ABOUT 1000
TO 1500 FEET THICK DEPENDING ON THE LOCATION...WITH A STEEP
INVERSION JUST ABOVE IT.  AT UPPER LEVELS THE UPPER LEVEL LOW THAT
PRODUCED RAIN AND SNOW YESTERDAY OVER IOWA IS NOW SHIFTING RAPIDLY
SOUTH ACROSS MISSOURI.  CLOUDS...BUT LITTLE RAIN IS CONTINUING TO
AFFECT SOUTHERN MISSOURI AND INTO KENTUCKY AND TENNESSEE.   ..LE..

&&

.SHORT TERM...TONIGHT AND MONDAY...
STRATUS REMAINS THE MAIN FORECAST CHALLENGE.  THE LARGE SCALE MODELS
WE ARE USED TO DEPENDING UPON HAVE NOT EVEN INITIALIZED THE LOW
LEVEL MOISTURE ASSOCIATED WITH THE STRATUS CORRECTLY.  THUS...THESE
MODELS ARE OF LITTLE USE IN PREDICTING IT.  OF THE MESOSCALE
MODELS...ONLY THE HRRR SEEMS TO HAVE ANY SORT OF HANDLE ON THE
STATUS OF THE STRATUS.  THUS...BETWEEN IT...EXPERIENCE AND
NOWCASTING TECHNIQES ARE ABOUT THE ONLY DECENT FORECAST TOOLS
TODAY.  SINCE THE MOISTURE IS TRAPPED BENEATH THE SURFACE RIDGE
AXIS...ANTICIPATE THE STRATUS SHOULD REFORM AND SPREAD BACK
SOUTHEAST AGAIN THIS EVENING...ADVECTING ALONG IN THE NORTHWEST
925MB FLOW.  OVER THE DAKOTAS TODAY THINGS SEEM TO HAVE CLEARED
NICELY WHERE THESE WINDS TURNED WESTERLY AND THE DOWNSLOPE COMPONENT
COULD HELP ACT TO DRY AND WARM THIS LAYER...HELPING TO DISSIPATE THE
CLOUDS.  HOWEVER...DOWNSLOPE WILL NOT HELP US THIS FAR EAST AND THOUGH I
EXPECT THE 925MB WINDS TO TURN WESTERLY FOR US AFTER MIDNIGHT
TONIGHT THE STRATUS SHOULD LINGER THROUGH THE OVERNIGHT HOURS. UNDER
THE STRATUS LAST NIGHT MIN TEMPS ONLY DROPPED INTO THE MID TO UPPER
20S...SO HAVE CONTINUED THIS.

MONDAY MORNING AND AFTERNOON LOOKS LIKE OUR BEST OPPORTUNITY FOR
CLEARING OUT THIS BAND OF STRATUS.  THE WESTERLY 925MB FLOW
STRENGTHENS TO 925MB...SOME WARM AIR ADVECTION AT THAT LAYER SHOULD
HELP TO DISSIPATE IT...ALONG WITH SHEER BODILY ADVECTION.  IT IS
NOTORIOUSLY HARD TO GET RID OF STRATUS THIS TIME OF YEAR...BUT THAT
IS USUALLY DUE TO ESTABLISHED SNOWCOVER. HOPEFULLY WITH THE SNOW
GONE FOR OUR AREA WE CAN GET RID OF THE STRATUS SOONER.
ANTICIPATING MORE CLOUD COVER OVER THE EAST HAVE KEPT MAX TEMPS
THERE COOLER...BUT NOT AS COOL AS THE NORTHWEST IS TODAY.
OTHERWISE...40-45 IS NOT UNREASONABLE AS LONG AS WE CLEAR BY EARLY
AFTERNOON.   ..LE..


.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...
FORECAST FOCUS ON POTENTIAL FOR FLURRIES MONDAY NIGHT AND TUESDAY
OTHERWISE MAINLY A DRY PERIOD. BRIEF SHOT OF ARCTIC AIR AT THE END
OF THE NEW WORK WEEK.

MONDAY NIGHT AND TUESDAY...COLD FRONT TO ARRIVE MONDAY NIGHT WITH
POTENTIAL FOR SOME FLURRIES OR BRIEF LIGHT SNOW. EXTENSIVE LOW
STRATUS TO DEVELOP BEHIND THE FRONT AS WE COLD ADVECT MONDAY NIGHT
WITH LOW CLOUDS CONTINUING ON TUESDAY AS SURFACE WINDS TURN
NORTHEAST. WILL CONTINUE WITH SLIGHT CHANCE POPS IN OUR SOUTH BUT
EVEN THE ECM HAS BACKED OFF ON QPF AMOUNTS. TEMPERATURES ON TUESDAY
ONLY COOL DOWN TO NEAR NORMAL FOR EARLY FEBRUARY. MAXIMUM
TEMPERATURES EXPECTED TO BE IN THE 30S.

TUESDAY NIGHT THROUGH THURSDAY...EXTENSIVE LOW STRATUS TO REMAIN
TUESDAY NIGHT AND FOR MOST OF WEDNESDAY WITH FORECAST SOUNDINGS
INDICATING NORTHEAST LOW LEVEL WINDS. WILL TRY TO CLEAR THE SKIES
OUT BY WEDNESDAY NIGHT AS WINDS TURN WEST TO SOUTHWEST. MAX TEMPS
ABOUT NORMAL WITH HIGHS IN THE 30S TO NEAR 40.

THURSDAY NIGHT THROUGH SATURDAY NIGHT...TROUGH STRONGLY DIGS INTO
THE MIDWEST/GREAT LAKES TIED TO A DEEP LOW NEAR HUDSON BAY. THIS
SENDS AN ARCTIC FRONT SWEEPING RAPIDLY THROUGH THE DVN CWA THURSDAY
NIGHT. HOWEVER DUE TO THE LACK OF SIGNIFICANT SNOW COVER TO OUR
NORTH AND NO SNOW COVER IN THE DVN CWA THIS AIRMASS WILL BE MODIFIED
BY THE TIME IT GETS HERE. THE COLDEST DAY WILL BE FRIDAY BUT
SATURDAY WONT EXACTLY BE A PICNIC EITHER. HIGHS WILL BE IN THE MID
20S NORTH TO LOWER 30S SOUTH WITH LOWS MAINLY IN THE TEENS. WARM
ADVECTION ALREADY UNDERWAY BY SATURDAY NIGHT AS ARCTIC HIGH PRESSURE
SHIFTS INTO THE OHIO VALLEY RETURNING SOUTH WINDS TO THE REGION.

SUNDAY...NICE WARM-UP BEGINS AS UPPER LEVEL FLOW BECOMES ZONAL TO
SOUTHWEST WITH SOUTHWEST SURFACE WINDS. MAX TEMPS SHOULD PUSH WELL
INTO THE 30S NORTH TO LOWER 40S SOUTH. EVEN WARMER TEMPERATURES
EARLY NEXT WEEK.

..HAASE..

&&

.AVIATION... /ISSUED 1214 PM CST SUN FEB 5 2012/

LARGE AREA STRATUS AND FOG WITH IFR TO LIFR CONDITIONS WAS
CONTINUING TO AFFECT MUCH OF IOWA. THIS STRATUS IS TRAPPED
UNDERNEATH A STRONG HIGH PRESSURE RIDGE OVER THE CENTRAL PLAINS.
IT WILL GRADUALLY SHIFT SOUTHEAST TODAY AND TONIGHT. THE EASTWARD
PROGRESS OF THE STRATUS HAS STALLED OR SLOWED DOWN...AND EXPECT A
CERTAIN AMOUNT OF RETREAT THIS AFTERNOON AS THE SUNSHINE WORKS TO
DISSIPATE IT. IT ALSO HELPS THAT THE STRATUS IS THIN...LATEST
PIREPS INDICATE THAT CLOUD TOPS ARE AROUND 1500 FT AGL. KDBQ...
KMLI AND KBRL SHOULD REMAIN NEAR THE EDGE OF THE STRATUS AND HAVE
INCLUDED TEMPOS GROUPS FOR THIS AFTERNOON. KCID IS LIKELY TO
REMAIN IFR IN THE STRATUS...BUT HAVE GONE OPTIMISTIC WITH A SHORT
TEMPO GROUP FOR VFR AS WELL. NEAR SUNSET EXPECT THE STRATUS TO
EXPAND AGAIN...AND CONDITIONS WILL DETERIORATE BACK TO IFR OR EVEN
LIFR FOR MOST OF THE NIGHT. THE SURFACE RIDGE FINALLY SHIFTS EAST OF
THE AREA MONDAY MORNING...AND EXPECT THE STRATUS TO FINALLY MOVE
OUT BY 14-16Z AND LEAVE US WITH VFR CONDITIONS. WINDS THROUGH
PERIOD TO REMAIN LIGHT...BUT WILL BE LIGHT NORTH THIS AFTERNOON
AND GRADUALLY SWITCH TO WEST LATE TONIGHT AND EARLY MONDAY
MORNING.   ..LE..

&&

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

$$

LE/HAASE

NWS DVN Office Area Forecast Discussion