Small Craft Advisory 10, NWS Northern Indiana

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
633 AM EDT SUN MAR 16 2014

.SYNOPSIS...
ISSUED AT 630 AM EDT SUN MAR 16 2014

UNSEASONABLY COLD TEMPERATURES CAN BE EXPECTED TODAY AND TONIGHT
AS COLD ARTIC HIGH PRESSURE NOSES INTO THE REGION. LOOK FOR HIGHS
TODAY ONLY IN THE MIDDLE 20S NORTH TO LOWER 30S SOUTH. LOWS
TONIGHT WILL DROP INTO THE SINGLE DIGITS NORTH AND MID TEENS
SOUTH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM EDT SUN MAR 16 2014

ANOTHER BENIGN AND COLD SHORT TERM PERIOD YET SEVERAL MINOR CONCERNS
AND QUESTIONS DEVELOPING WITH REGARDS TO CLOUDS...TEMPERATURES AND
EVEN PCPN EARLY THIS MORNING. SHORT RANGE GUIDANCE NOT HANDLING
CLOUDS AND COLD AIR ADVECTION WELL OVER OUR AREA EARLY THIS MORNING.
MOS GUIDANCE GENERALLY 3 TO 6 DEGREES TOO COLD AT 06Z AND HI RES 2M
TEMPS NOT MUCH BETTER. COLD AIR ADVECTION IS UNDERWAY WITH
BAROCLINIC ZONE SAGGING SOUTH BUT IT IS SLOWER THAN MODELS AND
GUIDANCE SUGGEST. THIS IN PART DUE TO EXPANDING AREA OF
STRATOCUMULUS CLOUD DECK RIDING EAST ALONG THE BAROCLINIC ZONE WITH
WEAK FGEN FORCING. SOME ADDITIONAL CONVERGENCE FROM STRONG LOW
PRESSURE SYSTEM TO OUR SOUTH AND ENCROACHING HIGH PRESSURE FROM THE
NORTH. THIS IS LEADING TO LIGHT SNOW OVER NORTH CENTRAL IL WITH A
SLOW MOVEMENT EAST. HOWEVER...PCPN IS RUNNING INTO DRIER LOW LEVEL
AIR AND SHOULD STRUGGLE TO MOVE INTO WESTERN CWA. WILL KEEP LOW
CHANCE POP IN WESTERN AREAS THROUGH 12Z GIVEN RADAR TRENDS AND
PROXIMITY.

HAVE MADE AN ATTEMPT TO MANUALLY EDIT HOURLY TEMP GRIDS BASED ON
OVERALL TRENDS LAST FEW HOURS. SIMILAR TO LAST NIGHT...INHERITED MAX
T GRIDS FOR TODAY SEVERAL DEGREES COLDER THAN TEMPS AT 07Z. WHILE
TEMPS WILL CONTINUE TO FALL THROUGH DAYBREAK...DOUBT THAT THEY CAN
REACH LOWS AS PREVIOUSLY ADVERTISED GIVEN SLOWER FALL AND INCREASING
CLOUDS. THUS WITH A SLIGHTLY WARMER START WILL HAVE TO MAKE SOME
UPWARD ADJUSTMENTS TO MAX T GRIDS FOR TODAY DESPITE COLD AIR ADVECTION.
EXPECT NORTHERN AREAS TO SEE SOME SUN AS CLOUDS THIN AND DRIER AIR
AND SUBSIDENCE WORK IN. THIS SHOULD ALLOW A SLIGHT REBOUND OF TEMPS
WITH MID MARCH SUN BUT HIGHS STILL REMAINING IN THE MID 20S. FURTHER
SOUTH WHERE CLOUDS WILL HOLD ON FOR MUCH OF THE DAY ON NORTHERN
PERIPHERY OF SOUTHERN STREAM WAVE...EXPECT TEMPS TO REMAIN NEARLY
STEADY FROM MORNING LOWS IN THE MID TO UPPER 20S.

SUBSIDENCE AND DRIER AIR WILL CONTINUE TO WORK SOUTH THIS EVENING
AND EVENTUALLY CLEAR SKIES ACROSS ENTIRE CWA. WITH ARCTIC HIGH
SLIDING ACROSS THE GREAT LAKES SHOULD SEE WINDS DIMINISH TONIGHT.
WHILE WEAK GRADIENT STILL EXPECTED...TEMPS SHOULD PLUMMET INTO TEENS
WITH LOWER DIGITS OVER FAR NORTHERN AREAS. REMAINED CAUTIOUS WITH LOWS
GIVEN RECENT FORECAST COLD BIAS OF 3 TO 5 DEGREES FOR MIN T ACROSS
OUR AREA.

&&

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 357 AM EDT SUN MAR 16 2014

A TRANSITION TO A FLATTER/MORE PROGRESSIVE PATTERN IS EXPECTED THIS
PERIOD. MONDAY INTO TUESDAY WILL FEATURE FAIR WX AND A PRONOUNCED
WARMING TREND IN ADVANCE OF AN UPPER LEVEL TROUGH MODELED TO
TRANSLATE THROUGH THE REGION TUESDAY NIGHT INTO WEDNESDAY. POTENT PV
ANOMALY PIVOTING THROUGH THE BASE OF THIS FEATURE AND SUPPORTIVE JET
STRUCTURE WILL FORCE A RELATIVELY DEEP SFC CYCLONE NORTHEAST INTO
THE WESTERN/NORTHERN GREAT LAKES BY LATER TUESDAY NIGHT - WEDNESDAY.
SHOULD SEE A SOMEWHAT NARROW LINE OF RAIN SHOWERS ACCOMPANY THE
TRAILING COLD FRONT BUT WILL HOLD WITH CHANCE POPS FOR NOW GIVEN
TIMING DIFFERENCES. COULD SEE A FEW POST FRONTAL RAIN AND SNOW
SHOWERS ACROSS MAINLY NORTHERN AREAS WEDNESDAY AFTN/EVE AS
DEFORMATION/TROUGH AXIS PIVOTS THROUGH WITH CAA BURST. FAIR WX
RETURNS THURSDAY BEFORE THE NEXT PACIFIC SHORTWAVE AND DEVELOPING
FRONTAL WAVE WORKS EAST AND BRINGS THE NEXT CHANCE FOR RAIN
(POSSIBLY MIXING WITH SNOW IN THE NORTH) FRIDAY INTO FRIDAY NIGHT.
00Z ENSEMBLES AND OPERATIONAL RUNS CONTINUE TO DIFFER ON AMPLITUDE
OF THIS WAVE RESULTING IN LOWER CONFIDENCE ON TIMING OF RAIN CHANCES
AND TEMPS BEYOND THURSDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 630 AM EDT SUN MAR 16 2014

MID LEVEL CLOUDS HAVE SPREAD ACROSS THE REGION. RADAR SHOWING SOME
RETURNS JUST SOUTHWEST OF KSBN BUT DRY NORTHEAST LOW LEVEL FLOW
CONTINUES TO ERODE THIS PCPN AS IT TRIES TO MOVE EAST. KEPT
CONDITIONS VFR AT TAF SITES WITH SKIES CLEARING LATER TODAY.
STILL EXPECT BRISK NORTHEAST WINDS TODAY IN THE 12 TO 18 KNOT
RANGE WITH GUSTS BETWEEN 20 AND 25 KTS.

&&

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

SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...STEINWEDEL
AVIATION...LASHLEY

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