Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 290949
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
449 AM CDT MON JUN 29 2015

.UPDATE...
ISSUED AT 424 AM CDT MON JUN 29 2015

LOOKING AT WEB CAMS AND OBSERVATION SITES HAS INDICATED THE FOG
HAS WORSENED AND MANY LOCATIONS ARE SOCKED IN WITH VISIBILITIES OF
1/4 MILE OR LESS. THEREFORE...I HAVE ISSUED A DENSE FOG ADVISORY
FOR THE ENTIRE CWA UNTIL 9 AM. IF THE FOG DISSIPATES SOONER THAN
THE ADVISORY CAN BE CANCELLED.

&&

.SYNOPSIS...
ISSUED AT 345 AM CDT MON JUN 29 2015

LIGHT TO CALM WINDS AND WET GROUND HAS LED TO THE DEVELOPMENT OF
GROUND FOG ACROSS MUCH OF THE CWA. LOOKING AT WEB CAMS AND
OBSERVATIONS THE VISIBILITIES WERE HIGHLY VARIABLE AND A SPECIAL
WEATHER STATEMENT HAS BEEN ISSUED TO COVER THIS SITUATION. 3 AM
TEMPERATURES WERE IN THE MID 50S NORTH TO MID 60S SOUTH ACROSS THE
CWA. A WEAK VORT MAX IN WI WAS CAUSING A FEW SHOWERS THERE WHILE A
STRONGER SHORT WAVE WAS SEEN ON WATER VAPOR LOOPS IN MANITOBA AND
DROPPING SOUTHWARD.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT MON JUN 29 2015

FORECAST FOCUS ON RAIN CHANCES.

TODAY...AREAS OF FOG SHOULD DISSIPATE BY 8 AM OR SO AND THEN
ATTENTION TURNS TO CHANCES FOR SHOWERS AND THUNDERSTORMS. WILL
MENTION SLIGHT CHANCES FOR SHOWERS THIS MORNING AND THEN INCREASE
POPS THIS AFTERNOON FOR THUNDERSTORMS. FORECAST SOUNDINGS INDICATE
WE REACH CONVECTIVE TEMPERATURES BY AROUND NOON WITH STEEPENING
LAPSE RATES...AND NO CAP IN PLACE. THE HRRR INDICATES SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS ALL OF THE CWA THIS AFTERNOON
WHILE OTHER MODELS ARE FAIRLY SIMILAR. THE SEVERE HAILERS SHOULD
REMAIN NORTH ACROSS MN AND WESTERN WI AIDED BY THE DECENT MANITOBA
WAVE AND COLDER AIR ALOFT. HOWEVER...SOME OF THESE STORMS MAY
DRIFT INTO NORTHEAST IA LATER THIS AFTERNOON AND EARLY EVENING
WITH THE POTENTIAL FOR SMALL HAIL AND GUSTY WINDS. SHEAR IS WEAK
AND SBCAPES ARE PROGGED AT 1000-2000 J/KG. HOWEVER...IF TEMPERATURES
CAN WARM MORE THAN EXPECTED THAN AN ISOLATED LARGE HAIL IS NOT OUT
OF THE QUESTION WITH FREEZING LEVELS AT 11K FT. SPC HAS A MARGINAL
RISK FOR THE POTENTIAL FOR STRONGER STORMS IN OUR NW CWA. THERE
SHOULD BE PLENTY OF CLOUD COVER AGAIN WITH SOME PEEKS OF SUNSHINE.
THIS WILL KEEP AFTERNOON TEMPERATURES IN THE 70S AT MOST LOCATIONS.

TONIGHT...AT LEAST SCATTERED SHOWERS AND STORMS THIS EVENING WILL
GRADUALLY DIMINISH WITH LOSS OF HEATING LATER THIS EVENING. THEN
WILL CARRY SMALL POPS AFTER MIDNIGHT AS THE NAM/GFS INDICATE SOME
LINGERING QPF WITH ANY WEAK VORT MAX IN THE DEEP NORTHWEST FLOW.
HOWEVER...THE ECMWF IS COMPLETELY DRY THIS EVENING AND OVERNIGHT.
MINIMUM TEMPERATURES WILL RANGE FROM THE LOWER TO MID 60S.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 345 AM CDT MON JUN 29 2015

NOT MUCH CHANGE IN THE OVERALL PATTERN WITH NORTHWEST FLOW ALOFT TO
PREVAIL THROUGH MUCH OF THE PERIOD KEEPING TEMPS NEAR TO BELOW
NORMAL WHILE ALSO LIMITING ANY ORGANIZED SEVERE POTENTIAL. WILL SEE
PERIODIC RAIN CHANCES AS SEVERAL UPPER LEVEL DISTURBANCES TRANSVERSE
THE REGION. ONE SUCH DISTURBANCE OFF THE PACIFIC NW COAST EARLY THIS
AM FAIRLY VIGOROUS LOOKING PER SATELLITE REPRESENTATION. THIS ENERGY
WILL CREST THE WESTERN HEAT DOME NEXT 24 HOURS THEN HEAD SE AND
INTERACT WITH IMPRESSIVE LOW LEVEL MOISTURE CONVERGENCE AND
BAROCLINIC ZONE (SQUEEZED BETWEEN DRIER EASTERLY FLOW OFF LAKE MI
AND ADVECTION OF DRIER AIR WITH SOUTHWEST FLOW OFF EASTERN ROCKIES
INTO KS) FOR WIDESPREAD SHOWERS AND STORMS WITH POTENTIAL FOR HEAVY
RAIN TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. THE MAIN CHALLENGE IS JUST
WHERE DOES THIS BATTLE ZONE AND HIGHER PROBABILITIES OF PRECIP AND HEAVY
RAIN SET UP. LAST SEVERAL RUNS OF GFS TRENDING FROM SOUTH OF I-70 TO
NEAR THE IA/MO BORDER CLOSER TO LAST FEW RUNS OF NAM. MEANWHILE...THE
ECMWF IS A BIT STRONGER WITH THE GREAT LAKES HIGH AND CONSEQUENTLY
WITH THE DRIER EASTERLY FLOW... AND IS ALSO SLOWER WITH MAIN SURGE OF
MOISTURE FOCUSING MORE LATER WEDNESDAY AND WEDNESDAY NIGHT NEAR THE
FAR SOUTHERN CWA AND ESPECIALLY JUST SOUTH/WEST OF CWA. GIVEN THE
STRENGTH OF FORCING WOULD ANTICIPATE THE THREAT FOR RAINFALL AMOUNTS OF
1-2+ INCHES WHERE THIS SETS UP AND WILL NEED TO BE WATCHED VERY CAREFULLY
FOR SOUTHERN CWA WHERE GROUND IS SATURATED AND RIVER LEVELS HIGH FROM
SEVERAL ROUNDS OF HEAVY RAINFALL WITHIN THE PAST WEEK OR SO. GIVEN THE
MODEL CONSISTENCY AND TIMING ISSUES I HAVE KEPT POPS IN THE CHANCE CATEGORY
FOR NOW TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH HIGHEST FAR SOUTH.

IN THE WAKE OF THIS SYSTEM WOULD ANTICIPATE 24+ HRS OF DRY AND PLEASANT
WEATHER THURSDAY POSSIBLY INTO FRIDAY WITH SURFACE RIDGING AND EASTERLY FLOW.

THEN...OPERATIONAL GFS AND MANY OF GFS ENSEMBLE MEMBERS ALONG WITH HI-RES
ECMWF SUGGEST ANOTHER DISTURBANCE ACCOMPANIED BY RAIN CHANCES ESPECIALLY THE
SOUTHERN CWA DEVELOPING FRIDAY AND LINGERING INTO FRIDAY NIGHT. IF THIS
TIMING HOLDS THEN HAVE AN OPPORTUNITY TO SNEAK IN A DRY AND SEASONABLE 4TH OF
JULY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 449 AM CDT MON JUN 29 2015

WIDESPREAD LIFR CONDS IN FG TIL 14Z/29. THEN VFR CONDS WITH
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING.
NORTHWEST WINDS AROUND 10 KNOTS OR LESS.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR BENTON-
     BUCHANAN-CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-
     IOWA-JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
     MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.

IL...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR BUREAU-
     CARROLL-HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-
     MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.

MO...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR CLARK-
     SCOTLAND.

&&

$$

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


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