000
FXUS63 KDVN 130445
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1145 PM CDT SUN MAY 12 2013

.SYNOPSIS...
ISSUED AT 240 PM CDT SUN MAY 12 2013

ANOTHER BEAUTIFUL BUT VERY COOL LATE SPRING DAY WITH CRYSTAL BLUE
SKIES AND MODERATELY GUSTY NW WINDS. TEMPERATURES AT 2 PM ARE
MOSTLY IN THE LOWER TO MIDDLE 50S...OR ALMOST 20 DEGREES BELOW
NORMAL. UPSTREAM ANALYSIS SHOWS WARM AIR ADVECTION TO KICK IN
WITHIN 24 HOURS AS SURFACE HIGH PRESSURE MOVES EAST. PERSISTENCE
UPSTREAM UNDER SURFACE HIGH THIS MORNING SUPPORTS CALM WINDS AND
FROST RISK TONIGHT. MID TO LATE WEEK TEMPERATURES TO RISE ABOVE
NORMAL WITH INCREASING CHANCES OF SHOWERS AND STORMS WITH RETURN
TO ZONAL FLOW.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 240 PM CDT SUN MAY 12 2013

TONIGHT...WILL ISSUE ANOTHER FROST ADVISORY OVER ROUGHLY EASTERN
1/2 OF AREA. THIS IS IN ADDITION OF THE FROST ADVISORY OVER NW 1/3
OF AREA LAST NIGHT WHERE SEVERAL REPORTS OF PATCHY TO AREAS OF
FROST OCCURRED. THIS IS ONE OF THE LATEST INSTANCES OF FROST IN
THE AREA OVER THE PAST 15 YEARS...IF NOT LONGER. LOCAL TOOLS AND
PERSISTENCE UPSTREAM SUPPORT GOOD DECOUPLING AFTER MIDNIGHT WITH
CLEAR SKIES AND LIGHT WINDS FOR TEMPERATURES TO FALL TO NEAR 32
DEGREES FOR SEVERAL HOURS...ESPECIALLY EAST OF THE I-380 CORRIDOR
AND HIGHWAY 218. AREAS OF FROST MAY BE ESPECIALLY NOTICEABLE AROUND
SUNRISE ALONG MISSISSIPPI...WAPSIPINICON AND ROCK RIVER VALLEYS.
MINS TO SHOULD SETTLE AROUND 32F IN NE WITH POCKETS TO NEAR 30F
POSSIBLE IN FAVORED LOW LYING LOCATIONS WITH UPPER 30S SW SECTIONS.
THIS WILL RESULT IN MINS AGAIN WITHIN A FEW DEGREES OF AREA RECORD
LOWS MANY SPOTS.

MONDAY...WARMING TREND TO COMMENCE WITH SOUTH WINDS INCREASING BY
AFTERNOON. HIGHS IN THE LOWER 60S NE TO LOWER 70S SW SECTIONS WITH
ISOLATED MOSTLY SPRINKLES TO LIGHT SHOWERS FROM MID LEVEL FORCING
ALONG ELEVATED WARM FRONT OVER NE 1/4 OF THE AREA AFTER 21Z. WINDS
MAY GUST OVER WEST SECTIONS TO NEAR 20 MPH IN THE AFTERNOON.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 240 PM CDT SUN MAY 12 2013

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY...
SOME VERY LIGHT SHOWERS/SPRINKLES ASSOCIATED WITH A THETA E GRADIENT
AND WAA SHOULD LINGER OVER THE NORTHEAST PART OF THE CWFA DURING THE
EVENING BEFORE DISSIPATING. OTHERWISE...DRY CONDITIONS ARE EXPECTED.

TUESDAY WILL BE DRY AND WARM. THE QUESTION IS HOW WARM WILL IT GET.
FCST SOUNDINGS SHOW THE INVERSION REMAINING IN PLACE WITH MIXING
MAYBE UP TO 900MB. LOW LEVEL LAPSE RATES AT BEST GET TO 6.5C/KM BY
MID AFTERNOON SUGGESTING LIMITED MIXING. WINDS REMAIN SOUTHERLY
UNTIL MID AFTERNOON BEFORE TURNING SOUTHWEST OVER THE WESTERN THIRD
OF THE CWFA. GENERALLY STRONG SOUTHWEST FLOW IS NEEDED TO GET VERY
WARM AROUND HERE. THE UPPER LEVEL FLOW IS WESTERLY WHICH IS NOT
CONDUCIVE TO GETTING EXTREMELY WARM AND THE AREA IS EXTREMELY
GREEN/MOIST ATTM SO CONSIDERABLE ENERGY WILL GO INTO
EVAPOTRANSPIRATION. ALL OF THIS SUGGESTS 80 TO 85 ACROSS THE CWFA
WITH PERHAPS SOME UPPER 80S IN THE FAR WESTERN CWFA.

TUES NIGHT/WED THE FRONT MOVES INTO THE AREA. MCS/LIFT TOOLS SUGGEST
NOT MUCH IN THE WAY OF PRECIPITATION ASSOCIATED WITH THE FRONT.
HOWEVER...GIVEN THE WAA AHEAD OF THE FRONT SOME SHOWERS COULD
DEVELOP DURING LATE TUESDAY EVENING/OVERNIGHT. IF SHOWERS DO DEVELOP
THEY WOULD LINGER INTO WEDNESDAY MORNING. DIURNAL HEATING AND AN
APPROACHING LOW SHOULD THEN ALLOW SHOWERS AND THUNDERSTORMS TO
DEVELOP DURING THE AFTERNOON HOURS.

WEDNESDAY NIGHT ON...
THE MODEL CONSENSUS CONTINUES THE THEME OF AN ACTIVE SECOND HALF OF
THE WEEK AND NEXT WEEKEND. THE CONSENSUS HAS SCHC/CHC POPS FROM WED
NIGHT THROUGH FRIDAY NIGHT. THE OVERALL PATTERN SUGGESTS THE
POSSIBILITY OF ORGANIZED NOCTURNAL THUNDERSTORM COMPLEXES THROUGH
FRIDAY.

THE MODELS DIVERGE SOMEWHAT FOR SAT/SUN IN REGARDS TO THE TIMING OF
THE NEXT SHORTWAVE AND COLD FRONT. THE CONSENSUS DOES RAISE POPS
INTO THE CHC/LIKELY CATEGORY OVER THE WEEKEND INDICATING A MORE
ORGANIZED RAIN SHOULD BE SEEN WITH THE NEXT STORM SYSTEM.

08

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1138 PM CDT SUN MAY 12 2013

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY EVENING. HIGH PRESSURE
WILL MOVE THROUGH EARLY MONDAY MORNING. MOSTLY CLEAR SKIES AND
LIGHT WIND ASSOCIATED WITH THE HIGH WILL CREATE FAVORABLE
CONDITIONS FOR FROST...ESPECIALLY NEAR AND EAST OF THE
MISSISSIPPI RIVER. AS THE HIGH MOVES EAST OUT OF THE AREA...SOUTH
WINDS WILL PICKUP AND CONTINUE THROUGH MONDAY EVENING. MID CLOUDS
WILL MOVE THROUGH DURING THE AFTERNOON AND EVENING. THERE MAY BE
SOME LIGHT RAINSHOWERS/SPRINKLES ASSOCIATED WITH THE
CLOUDS...ESPECIALLY OVER NORTHWEST IL.

&&

.CLIMATE...
ISSUED AT 240 PM CDT SUN MAY 12 2013

RECORD LOWS FOR MAY 13...

MOLINE.........31 IN 1971
CEDAR RAPIDS...34 IN 1997
DUBUQUE........30 IN 1888
BURLINGTON.....35 IN 1971

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...FROST ADVISORY UNTIL 7 AM CDT MONDAY FOR CEDAR-CLINTON-DELAWARE-
     DUBUQUE-JACKSON-JONES-MUSCATINE-SCOTT.

IL...FROST ADVISORY UNTIL 7 AM CDT MONDAY FOR BUREAU-CARROLL-HENRY IL-
     JO DAVIESS-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-
     WARREN-WHITESIDE.

MO...NONE.
&&

$$

SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...DLF
CLIMATE...NICHOLS