Area Forecast Discussion
Issued by NWS Des Moines, IA

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KDMX 292048
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
348 PM CDT WED APR 29 2015

.SHORT TERM /TONIGHT/...
ISSUED AT 347 PM CDT WED APR 29 2015

BEAUTIFUL WEATHER WILL CONTINUE TO HOLD UP THROUGH THE REST OF TODAY
AND TONIGHT AS HIGH PRESSURE CONTINUES TO DOMINATE THE REGION. FAIR
WEATHER CU OVER THE SOUTHEAST HALF OF THE STATE WILL MOVE OUT AND
GIVE WAY TO CLEAR SKIES LATER THIS EVENING. SOME OF THE
MODELS...INCLUDING THE EURO AND NAM...TRY AND BRING SOME MID-LEVEL
CLOUD COVER OVER EASTERN IOWA THIS EVENING BUT WITH PLENTY OF DRY
AIR AND LITTLE TO NO LIFT...KEPT SKIES CLEAR OVERNIGHT.  LOWS
OVERNIGHT MAY REACH THE UPPER 30S ACROSS WESTERN IOWA AND LOW LYING
AREAS WHERE WINDS GO LIGHT TO CALM...BUT KEPT LOWS GENERALLY IN THE
LOW 40S WITH WINDS AROUND 5 KTS MUCH OF THE NIGHT.

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
ISSUED AT 347 PM CDT WED APR 29 2015

CLOSED UPPER LOW WILL DROP SWIFTLY FROM THE LAKE MICHIGAN EARLY
THURSDAY INTO THE CAROLINAS BY FRIDAY MORNING. AS THIS
OCCURS...THE MEAN UPPER FLOW WILL TRANSITION TO ZONAL DURING THE
DAY FRIDAY AS THE UPPER LOW DEPARTS FROM THE AREA. A WEAK SFC
BOUNDARY WILL FOLLOW AIDED BY THE ZONAL FLOW AND ENTER THE STATE
DURING THE DAY FRIDAY. HOWEVER WITH LARGE HIGH PRESSURE TO THE
SOUTHEAST AND RETURN FLOW DEVELOPING INTO THE STATE...THE BOUNDARY
WILL ERODE THROUGH THE DAY AND IS EXPECTED TO BE COMPLETELY
DISSIPATED BY FRIDAY NIGHT. THE BOUNDARY WILL BRING SOME
CONVECTIVE INSTABILITY WITH STEEPENING LAPSE RATES ALONG AND LOW
THETA-E DIFFERENCES BETWEEN THE TROPOPAUSE AND THE BOUNDARY
LAYER. THEREFORE...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE THROUGH THE DAY FRIDAY WITH BEST POTENTIAL OVER THE
NORTHWEST HALF OF THE STATE. ASSOCIATED CLOUD COVER MAY LINGER
THROUGH THE DAY AND MAY HOLD TEMPERATURES DOWN A BIT SHOULD A
PROLONGED STAY OCCUR.

SCATTERED THUNDERSTORMS REMAIN POSSIBLE ON SATURDAY. DESPITE THE
WASHED OUT SFC BOUNDARY...THE 850 MB BOUNDARY WILL HAVE SETTLED
SOUTH INTO NORTHERN MISSOURI AND WILL LIFT BACK NORTH ACROSS THE
STATE DURING THE DAY. SFC BASED INSTABILITY WILL INCREASE THROUGH
THE DAY WITH A SHORT WAVE ARRIVING FROM THE WEST. EXPECT A FEW
THUNDERSTORMS THROUGH THE AFTERNOON AND INTO THE EVENING HOURS.
THE NEXT BOUNDARY WILL DROP DOWN AND APPROACH FAR NORTHERN IOWA
LATE SUNDAY AND THEN STALL ACROSS THE STATE SUNDAY NIGHT INTO
MONDAY. THIS WILL BE THE BEGINNING OF A MORE ACTIVE PERIOD THROUGH
MUCH OF NEXT WEEK WITH NUMEROUS CHANCE FOR THUNDERSTORMS. PWAT
VALUES WILL APPROACH 1.5 INCHES AT TIMES THROUGH THIS PERIOD.
STORM MOTIONS LATE SUNDAY THROUGH TUESDAY WILL GENERALLY BE SLOW
AT 15 TO 25 KTS THEREFORE THE POTENTIAL FOR HEAVY RAINFALL DOES
EXIST. DEEP LAYER SHEAR WILL FAVOR MORE MULTICELLULAR STORMS
HOWEVER A FEW MORE ORGANIZED STORMS MAY OCCUR. WHILE NO WIDESPREAD
SEVERE WEATHER IS EXPECTED...LIKELY WILL HAVE A FEW SEVERE STORMS
DURING THIS PERIOD.

THE MEAN MID LEVEL FLOW WILL BECOME MORE SOUTHWESTERLY LATE
TUESDAY INTO WEDNESDAY WITH A SIGNIFICANT IMPULSE LIFTING THROUGH
THE FLOW DURING THE DAY WEDNESDAY. THIS SYSTEM COULD BRING A
BETTER POTENTIAL FOR SEVERE WEATHER SHOULD THE SYSTEM ARRIVAL OCCUR
DURING PEAK HEATING. BEYOND THAT...STILL SIGNIFICANT DIFFERENCES
ON HOW TO HANDLE THE UPPER LOW MOVING INTO THE NW CONUS WEDNESDAY.
THE GFS EVOLUTION OF THIS SYSTEM BEYOND THE EXTENDED IS
CLIMATOLOGICAL RARE AND LEADS TO LESS CONFIDENCE IN ITS SOLUTION
BY THE END OF NEXT WEEK.

&&

.AVIATION...29/18Z
ISSUED AT 1227 PM CDT WED APR 29 2015

QUIET TAF PERIOD WITH HIGH PRESSURE IN THE REGION. VFR CONDITIONS
THROUGHOUT WITH ONLY SOME FAIR WEATHER CUMULUS TODAY AND WINDS
AROUND 10 KTS OUT OF THE NORTH AND GUSTS TO AROUND 15 KTS AT
TIMES BEFORE SUBSIDING THIS EVENING.


&&

.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...CURTIS
LONG TERM...DONAVON
AVIATION...CURTIS


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.