Area Forecast Discussion
Issued by NWS Northern Indiana

Home | Current Version | Previous Version | Text Only | 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 KIWX 101721
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
ISSUED BY NATIONAL WEATHER SERVICE GRAND RAPIDS MI
121 PM EDT THU APR 10 2014

.SYNOPSIS...
ISSUED AT 1038 AM EDT THU APR 10 2014

A COLD FRONT WILL BE MOVING THROUGH THE REGION TODAY INTO TONIGHT.
SOUTHWESTERLY WINDS AHEAD OF THE FRONT WILL BE USHERING IN WARMER
AIR AND SOME MOISTURE. THIS WILL CREATE A CHANCE FOR SOME RAIN
TODAY INTO TONIGHT WITH SOME ISOLATED THUNDER. BY TOMORROW
MORNING THE FRONT AND RAIN WILL HAVE MOVED TO THE EAST AND SOUTH.
HIGH TEMPERATURES TODAY WILL RANGE FROM THE LOWER 60S NEAR LAKE
MICHIGAN TO THE MIDDLE 70S ALONG THE OHIO RIVER. LOWS TONIGHT WILL
RANGE FROM THE UPPER 30S IN SOUTHERN MICHIGAN TO THE LOWER 50S
NEAR THE OHIO RIVER. HIGHS TOMORROW WILL BE IN THE LOWER TO MIDDLE
60S.

&&

.UPDATE...
ISSUED AT 121 PM EDT THU APR 10 2014

MAIN CHANGES FOR TODAY WERE TO INCREASE WINDS AND BOOST HIGH
TEMPERATURES. MODEL GUIDANCE AND OBSERVATIONS INDICATE WINDS
SHOULD DECREASE SIGNIFICANTLY LATER TODAY AS THEY SHIFT TO THE
WEST IN CLOSER PROXIMITY TO THE COLD FRONT. GIVEN VERY DRY LOW LEVELS
SEEN ON AREA SOUNDINGS THIS MORNING...LITTLE OR NO RAIN HAS BEEN
REPORTED IN SPITE OF HEALTHY RADAR REFLECTIVITIES WELL OVER 30 DBZ.
WE WOULD EXPECT ENHANCED GUST POTENTIAL WITH PRECIPITATION AS IT
BRINGS DOWN STRONGER WINDS ALOFT. THE BACK EDGE OF THIS RELATIVELY
NARROW PRECIPITATION BAND IS RAPIDLY APPROACHING THE FORECAST
AREA...SO WE EXPECT DRY CONDITIONS TO RETURN BY THIS EVENING.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 351 AM EDT THU APR 10 2014

INCREASING SOUTHWESTERLY FLOW WILL CONTINUE ACROSS THE REGION AHEAD
OF A COOL FRONT THAT WILL DROP INTO THE AREA THIS AFTERNOON AND
EVENING. AS OF 2 AM...FRONT WAS LOCATED FROM N WISCONSIN TO EASTERN
NEBRASKA. 2 BANDS OF SHOWERS WERE LOCATED GENERALLY BEHIND THE FRONT
WITH THE INITIAL ONE (CLOSER TO THE FRONT) SHOWING SIGNS OF
WEAKENING. FORECAST CHALLENGE WILL BE TIMING/COVERAGE OF
SHOWERS...IMPACTS ON PRECIP AND CONVECTIVE POTENTIAL.

PARTLY TO MOSTLY SUNNY SKIES WILL PREVAIL INTO EARLY AFTERNOON WITH
CLOUD COVER INCREASING FROM NW TO SE THROUGH THE DAY. MAJORITY OF
THE MODELS CONTINUE TO KEEP PRECIP POST FRONTAL AND IN SEVERAL CASES
SLOW DOWN ITS ARRIVAL UNTIL LATER AFTERNOON/EARLY EVENING. TREND HAS
BEEN FOR SOME OF THE UPSTREAM SHOWERS TO DISSIPATE. HOWEVER...BIT OF
A CONCERN MONITORING IR SAT LOOP WITH COOLING CLOUD TOPS IN N
MISSOURI ON NOSE OF INCREASING MSTR WHERE A FEW SHOWERS ARE NOTED.
GFS ACTUALLY PICKS UP ON THIS SOMEWHAT AND BRINGS SOME LIGHT PRECIP
INTO FAR NW AREAS TOWARDS 18Z. TO FURTHER COMPLICATE THINGS...A
HANDFUL OF THE HIGH RES MODELS SHOW ADDITIONAL SHOWERS/EMBEDDED
STORMS BREAKING OUT ALONG AND JUST AHEAD OF THE FRONT DURING PEAK
HEATING/ARRIVAL OF MSTR PLUME AND STEEP LAPSE RATES. NOT FULLY
CONVINCED THE MSTR WILL GET HERE IN TIME...BUT ENOUGH SIGNALS TO
INTRODUCE A SLGT CHC OF THUNDER IN SE AREAS LATER THIS AFTERNOON.
WHILE SEVERE WEATHER IS NOT EXPECTED POTENTIAL EXISTS FOR SOME GUSTS
TO 50 MPH IN MORE ROBUST SHOWERS GIVEN STRONG WIND FIELDS. PRIOR
TO ANY PRECIP TEMPS SHOULD REBOUND NICELY INTO THE 60S ACROSS MOST
OF THE AREA WITH SE LOCATIONS POSSIBLY FLIRTING WITH 70.

FRONT WILL PASS THROUGH BY LATE EVENING WITH PRECIP QUICKLY
DEPARTING. WHILE AIR BEHIND THE FRONT WILL DROP OVERNIGHT LOWS 5 TO
10 DEGREES COOLER THAN TONIGHT...HARD TO CALL A COLD FRONT GIVEN
LOWS IN THE UPR 30S TO LOW 40S ARE RATHER SEASONABLE AND A NICE
REBOUND IN TEMPS IS EXPECTED INTO THE LONG TERM.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 351 AM EDT THU APR 10 2014

BRIEF PERIOD OF QUIET CONDITIONS TO END THE WEEK BUT ACTIVE WEATHER
RETURNS EARLY NEXT WEEK AS ANOTHER LONGWAVE TROUGH GRADUALLY SWINGS
THROUGH THE REGION AND LEADS TO ANOTHER ROUND OF MODERATE RAINFALL.
SOUTHERN GREAT LAKES WILL RESIDE IN AN AREA OF WEAK POSTFRONTAL
SUBSIDENCE ON FRIDAY WITH NEGATIVE THETA-E ADVECTION MAINTAINING DRY
CONDITIONS. A WEAK SHORTWAVE DOES CROSS THROUGH THE REGION LATE
FRIDAY BUT WHAT LITTLE CVA AND JET SUPPORT THERE IS BYPASSES US TO
THE NORTH AND EXPECT LITTLE MORE THAN SOME HIGH BASED CLOUDS DURING
THE AFTERNOON. THERMAL ADVECTIONS BEHIND THE EXITING FRONT ARE ALSO
VERY NONDESCRIPT GIVEN LARGELY ZONAL FLOW ALOFT. ALMOST NO CAA TO
SPEAK OF AND 850MB TEMPS REMAIN NEAR 4C ON FRIDAY. THESE THERMAL
PROFILES COMBINED WITH DEEP MECHANICAL MIXING UNDER A SCATTERED
MID/UPPER LEVEL CLOUD FIELD SHOULD PROMOTE ANOTHER DAY IN THE LOW TO
MID 60S. WAA INCREASES ON SATURDAY AS LONGWAVE TROUGH SWINGS THROUGH
THE ROCKIES AND SOUTHWEST FLOW RAMPS UP LOCALLY. COULD BE A FEW
ISOLATED SHOWERS SATURDAY AFTERNOON IN REGION OF MODEST ISENTROPIC
UPGLIDE BUT THE BEST LOW LEVEL CONVERGENCE/WARM FRONTOGENESIS SEEMS
TO BE FOCUSED TO OUR NORTH. MAIN STORY FOR SATURDAY WILL PROBABLY BE
THE WARM TEMPS DESPITE INCREASING CLOUD COVER. 850MB TEMPS RETURN TO
AROUND 10C ON SATURDAY IN WELL ESTABLISHED WARM SECTOR. FORECAST
SOUNDINGS ONCE AGAIN SHOW MIXING DEPTHS APPROACHING THE 850MB LEVEL
WITH AT LEAST FILTERED INSOLATION THAT COULD LEAD TO A SURPRISINGLY
WARM DAY. SOME OF THE LATEST MOS GUIDANCE ARE ALREADY SUGGESTING
HIGHS WELL INTO THE MID 70S. THIS MAY NOT BE OUT OF THE QUESTION
GIVEN THE EXPECTED LOW LEVEL PATTERN AND HAVE MADE SUBSTANTIAL
UPWARD ADJUSTMENTS TO SATURDAY`S HIGHS WITH VALUES IN THE LOW TO MID
70S.

00Z NWP SUITE BEGINNING TO CONVERGE ON A SOLUTION FOR EARLY NEXT
WEEK BUT IMPORTANT DIFFERENCES REMAIN. HIGH AMPLITUDE TROUGH TO
BECOME ESTABLISHED OVER THE MIDWEST BY LATE SUNDAY AS CLOSED LOW OFF
THE CALIFORNIA COAST MERGES WITH DIGGING NORTHERN STREAM TROUGH.
STRONG BAROCLINIC ZONE WILL BECOME ESTABLISHED FROM EASTERN CANADA
TO THE SOUTHERN PLAINS WITH THE POTENTIAL FOR MULTIPLE SURFACE WAVES
TO DEVELOP ALONG IT. THIS FRONTAL BOUNDARY WILL ALSO MOVE VERY
LITTLE FROM EARLY SUNDAY THROUGH LATE MONDAY AS THE UPPER LEVEL
PATTERN BECOMES INCREASINGLY AMPLIFIED AND ALIGNED NEARLY PARALLEL
TO THE FRONT. THIS WILL ALSO PROMOTE EFFICIENT NORTHWARD MOISTURE
TRANSPORT WITH PW VALUES APPROACHING 1.25 INCHES. THE MAIN QUESTION
REMAINS WHERE EXACTLY DOES THE FRONT SET UP AND WHERE WILL POTENTIAL
CONVECTIVE WAVES TRACK. THERE IS STILL A LOT OF UNCERTAINTY ON THESE
POINTS AND UNFORTUNATELY THAT WILL PROBABLY CONTINUE TO BE THE CASE
UNTIL THE EVENT BEGINS SATURDAY NIGHT. EXACT LOCATION OF BAROCLINIC
ZONE AND TIMING/TRACK OF WAVES OF PRECIP WILL ALSO HAVE A LARGE
IMPACT ON TEMPS...POPS...AND QPF/FLOOD POTENTIAL. FOR NOW WILL JUST
HIGHLIGHT LATE SUNDAY THROUGH MONDAY AS THE BEST CHANCE FOR
WIDESPREAD MODERATE RAIN AND PERHAPS A FEW EMBEDDED THUNDERSTORMS.
EXACT QPF AMOUNTS AND RESULTANT FLOOD POTENTIAL REMAIN IN DOUBT WITH
THE LATEST 00Z ECMWF STILL KEEPING THE AXIS OF HEAVIEST RAIN TO OUR
NORTHWEST WHILE THE GEM AND GFS ALIGN THE ACTIVE FRONTAL ZONE ALMOST
DIRECTLY OVERHEAD. WILL CONTINUE TO MONITOR MODEL TRENDS AND
GRADUALLY NAIL DOWN THE FORECAST DETAILS OVER THE COMING DAYS AS
AVAILABILITY OF OBSERVATIONAL DATA INCREASES. REGARDLESS OF RAINFALL
SPECIFICS...EXPECT AT LEAST A BRIEF SHOT OF WELL BELOW AVERAGE TEMPS
BEHIND THE FRONT LATE MONDAY THROUGH WEDNESDAY. HIGHS MAY STRUGGLE
TO GET ABOVE THE MID 40S WITH LOWS WELL BELOW FREEZING. IN
FACT...WOULDN`T BE SURPRISED AT ALL TO SEE A FEW SNOWFLAKES ON THE
BACK EDGE OF EXITING PRECIP MONDAY NIGHT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY)
ISSUED AT 556 AM EDT THU APR 10 2014

WINDS WILL INCREASE THIS MORNING AS WILL CLOUD COVER. CHANCES
FOR SHOWERS WILL INCREASE LATER THIS MORNING AT KSBN AND EXPAND SE
TO KFWA THIS AFTERNOON. OUTSIDE CHANCE FOR A RUMBLE OF THUNDER AT
KFWA BUT WILL LEAVE OUT OF TAFS FOR NOW. CIGS/VSBYS SHOULD REMAIN
VFR EVEN WITH ANY SHOWERS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

UPDATE...TJT
SYNOPSIS...LOTHAMER
SHORT TERM...FISHER
LONG TERM...AGD
AVIATION...FISHER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA






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