394
FXUS63 KIWX 222325
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
725 PM EDT THU AUG 22 2019
SYNOPSIS
ISSUED AT 723 PM EDT THU AUG 22 2019
HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS THE GREAT LAKES REGION
AND WILL BRING NEARLY PICTURE PERFECT WEATHER TO OUR AREA. EXPECT
DRY CONDITIONS THROUGH THE WEEKEND WITH COMFORTABLE TEMPERATURES
AND HUMIDITY LEVELS. CHANCES FOR RAIN RETURN LATE SUNDAY NIGHT.
HIGH TEMPERATURES WILL BE IN THE 70S THROUGH SUNDAY AND LOWS WILL
BE IN THE 50S. HAZARDOUS SWIMMING CONDITIONS ARE EXPECTED ON
SOUTHERN LAKE MICHIGAN FRIDAY WITH HIGH WAVE ACTION AND DANGEROUS
CURRENTS EXPECTED AT THE BEACHES.
SHORT TERM
(THIS EVENING THROUGH FRIDAY)
ISSUED AT 422 PM EDT THU AUG 22 2019
FAIRLY QUIET WEATHER IN THE SHORT TERM, WITH MAINLY DRY CONDITIONS
EXPECTED THROUGH FRIDAY. THE COLD FRONT RESPONSIBLE FOR RAIN SHOWERS
SOUTH AND EAST OF US 24 TODAY WILL CONTINUE TO DRIFT SOUTHWARD
TONIGHT, WITH SURFACE HIGH PRESSURE BUILDING IN OVER LAKE
SUPERIOR. THE RESULTING NNE WINDS WILL FILTER DOWN ACROSS LAKE
MICHIGAN LATE THIS AFTERNOON AND OVERNIGHT, BUILDING WAVES UP TO
AROUND 3 TO 5 FEET.
AS OF 4 PM, WAVES HAVE ALREADY CLIMBED TO 2 TO 3 FEET IN BERRIEN
COUNTY, MI AND JUST OVER 4 FEET IN LAPORTE COUNTY, IN. HAVE
ISSUED A SMALL CRAFT ADVISORY AND A BEACH HAZARDS STATEMENT FOR
THE LAPORTE COUNTY WATERS/BEACHES. WAVES IN THIS AREA WILL
APPROACH THE SHORE AT AT 30 TO 60 DEGREE ANGLE, WITH A PERIOD OF 5
TO 6 SECONDS. DANGEROUS CURRENTS, PARTICULARLY LONGSHORE AND
STRUCTURAL CURRENTS, ARE EXPECTED IN CONDITIONS LIKE THESE.
FURTHER NORTH IN BERRIEN COUNTY, MI KEPT THE MODERATE SWIM RISK
FOR NOW. EXPECTING WAVES TO BE SLIGHTLY LOWER (UP TO 4 FEET LATER
TONIGHT) AND WAVE ANGLES OF APPROACH ARE 30 DEGREES OR LESS
RELATIVE TO SHORE-WHICH MAKES STRONG OFFSHORE FLOWING CURRENTS
LESS LIKELY. THAT BEING SAID, IF CONDITIONS WORSEN MAY NEED TO
UPGRADE BERRIEN COUNTY TO A HIGH SWIM RISK AND ISSUE A BEACH
HAZARDS STATEMENT. IT IS LIKELY WE EXTEND THE BEACH HAZARDS
STATEMENT AND SMALL CRAFT ADVISORY THROUGH LATE FRIDAY EVENING, AS
WAVES ONLY DROP TO AROUND 2 FEET LATE FRIDAY MORNING BEFORE
CLIMBING BACK UP TO AROUND 3 TO 4 FEET IN THE AFTERNOON. WILL
LEAVE THIS DECISION TO THE EVENING/MIDNIGHT SHIFTS WHEN CONFIDENCE
MAY BE HIGHER.
SURFACE HIGH PRESSURE/DRY AIR SHOULD KEEP THINGS DRY FRIDAY
AFTERNOON, BUT SOME OF THE MODELS INDICATE WE COULD SEE A FEW POP UP
SHOWERS/STORMS IN THE AFTERNOON ON FRIDAY (18Z-00Z-ISH)AS THE MAIN
AXIS OF AN UPPER LEVEL TROUGH SWINGS THROUGH DURING PEAK HEATING.
FOR NOW, LEFT THE FORECAST DRY GIVEN LOW CONFIDENCE. HIGHS WILL BE
IN THE 70S.
LONG TERM
(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 422 PM EDT THU AUG 22 2019
SURFACE HIGH PRESSURE PREVAILS THROUGH SUNDAY NIGHT, SO EXPECT CLEAR
TO PARTLY CLOUDY SKIES AND DRY CONDITIONS. HIGH TEMPERATURES WILL
RANGE FROM THE LOW 70S TO AROUND 80F. LOWS FRIDAY NIGHT INTO
SATURDAY NIGHT WILL DROP INTO THE LOW TO MID 50S.
THE NEXT CHANCES FOR PRECIPITATION START MONDAY, ESPECIALLY TOWARDS
THE AFTERNOON HOURS. AN UPPER LEVEL LOW WILL TRAVERSE THE CANADIAN
PRAIRIE MONDAY AND DRAG A TROUGH INTO THE GREAT LAKES BY TUESDAY.
THE LOW BECOMES VERTICALLY STACKED SOUTHWEST OF HUDSON BAY TUESDAY
AFTERNOON AND EVENING, THEN SETTLES OVER THE BAY THURSDAY INTO
FRIDAY. THIS WILL BRING A TROUGH THROUGH MO/IA/IL/IN MONDAY INTO
TUESDAY. AT THE SURFACE, THE GFS BRINGS A SURFACE LOW UP FROM MO
INTO IL/IN BEFORE IT IS ABSORBED INTO THE STRONGER WAVE TO THE
NORTH. THIS LIFTS A WARM FRONT ASSOCIATED WITH THIS LOW NORTHWARD
THROUGH OUR CWA MONDAY, AND THEN THE TRAILING COLD FRONT WITH THE
STRONGER SYSTEM TO THE NORTH THROUGH OUR FORECAST AREA TUESDAY INTO
TUESDAY NIGHT. THERE ARE A FEW DISCREPANCIES BETWEEN MODELS WITH
RESPECT TO THE PLACEMENT OF THE NORTHERN STREAM LOW AND THE STRENGTH
OF THE LOW TO OUR SOUTHWEST. THE ECMWF IS WEAKER WITH THE UPPER
LEVEL LOW TO OUR NORTH (HUDSON BAY AREA) AND THE STRENGTH OF THE
TROUGH EXTENDING INTO MO/IA/IL/IN. AT THE SURFACE (TO OUR
SOUTHWEST), THERE IS JUST A TROUGH. THE GFS TAKES THE NORTHERN UPPER
LOW FURTHER NORTH AND THEN DEVELOPS A SEPARATE CLOSED LOW OVER
WESTERN LAKE SUPERIOR TUESDAY MORNING, AND DIGS THE TROUGH FURTHER
SOUTH AND EAST. THIS DEVELOPS THE SURFACE LOW TO OUR SOUTHWEST. SO
WHAT DOES THIS ALL MEAN? THERE ARE SLIGHT DIFFERENCES IN TIMING OF
THE INITIAL PRECIPITATION MONDAY (GFS STARTS SUNDAY NIGHT, ECMWF
LATE MONDAY MORNING IN THE SOUTHWEST). THE COLD FRONT TIMING IS
PRETTY CONSISTENT TUESDAY INTO TUESDAY NIGHT, BUT THE STRENGTH OF
THE FRONT AND THE AMOUNT OF PRECIPITATION IS GREATER WITH THE GFS.
ALL THIS IN MIND, I KEPT THE CONSENSUS POPS MON/TUESDAY, WITH A
DIMINISHING TREND FROM WEST TO EAST THROUGH TUESDAY EVENING.
PARTLY CLOUDY SKIES AND DRY CONDITIONS RETURN LATE TUESDAY NIGHT AND
LINGER THROUGH WEDNESDAY WITH ANOTHER SURFACE HIGH BUILDING IN
BEHIND THE FRONT. THURSDAY WE COULD SEE SOME CHANCES FOR RAIN
DEPENDING ON STRENGTH OF THE BOTH THE NEXT WAVE ROTATING AROUND THE
LOW IN HUDSON BAY, AND THE INCOMING HIGH PRESSURE OVER THE NORTHERN
PLAINS. ECMWF HOLDS OFF UNTIL FRIDAY AFTERNOON TO BRING THE SURFACE
COLD FRONT AND SUBSEQUENT PRECIPITATION CHANCES IN, BUT THE GFS
BRINGS THE FRONT THROUGH ON THURSDAY MORNING. KEPT LOW CHANCE POPS
IN FOR NOW. HIGHS MONDAY INTO THURSDAY WILL BE IN THE 70S AND LOW
80S. LOWS WILL BE IN THE 50S AND 60S. WITH GUSTY WEST TO NORTHWEST
WINDS BEHIND THE FRONT TUESDAY AFTERNOON INTO THURSDAY, A MODERATE
SWIM RISK IS POSSIBLE FOR LAKE MICHIGAN BEACHES.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 721 PM EDT THU AUG 22 2019
VFR THROUGH THE PERIOD AS HIGH PRESSURE MOVES INTO THE AREA. WINDS
GENERALLY FROM NORTHEAST AROUND 5 KTS OR LESS TONIGHT AND 5 TO 9
KNOTS ON FRIDAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...BEACH HAZARDS STATEMENT THROUGH FRIDAY MORNING FOR INZ003.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EDT FRIDAY FOR LMZ046.
SYNOPSIS...LASHLEY
SHORT TERM...MCD
LONG TERM...MCD
AVIATION...LASHLEY
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