323 AM CDT
NO MAJOR CHANGES IN FORECAST THINKING THROUGH THE WEEKEND AND INTO
NEXT WEEK. EARLY MORNING WATER VAPOR IMAGERY SHOWS OMEGA PATTERN IN
THE UPPER FLOW SLOWLY SHIFTING EASTWARD. AN UPPER TROUGH CONTINUES
TO SPIN NORTH OF NEWFOUNDLAND WITH AN UPPER LEVEL RIDGE AXIS
EXTENDING FROM THE OHIO VALLEY NORTHWARD TOWARD HUDSON BAY WHERE IT
FLATTENS. TO THE WEST...A LARGE CLOSED UPPER LOW CONTINUES TO SPIN
OVER UTAH/NEVADA WITH A SECONDARY CLOSED LOW DEVELOPING OVER EASTERN
WYOMING AND LIFTING NORTHWARD ALONG THE WESTERN PERIPHERY OF THE
RIDGE. ADDITIONAL ENERGY IS PUSHING EASTWARD TOWARD THE BRITISH
COLUMBIA COAST AND WILL HELP KICK THIS NEW CLOSED LOW TO THE NORTH
AND EAST AND ALLOW THE SOUTHERN PART OF THE LARGER SCALE TROUGH TO
ONCE AGAIN CUT OFF OVER THE FOUR CORNERS. AT THE SURFACE...HIGH
PRESSURE IS NOW CENTERED OVER THE MID-ATLANTIC STATES WITH LOW
PRESSURE DEEPENING OVER NORTHEASTERN WYOMING AND EASTERN MONTANA.
THE LOCAL AREA LIES IN THE INCREASING PRESSURE GRADIENT BETWEEN
THESE TWO SYSTEMS.
QUIET WEATHER WILL CONTINUE WITH THE AREA REMAINING UNDER THE
WESTERN PORTION OF THE RIDGE THROUGH THE WEEKEND. THE AMPLITUDE AND
ORIENTATION OF THE RIDGE WILL CHANGE AS ENERGY EJECTS FROM THE
WESTERN TROUGH AND MOVES ALONG THE WESTERN AND NORTHERN PERIPHERY OF
THE RIDGE. THE ACTIVE WEATHER WILL STAY TO THE WEST WITH THE WESTERN
TROUGH MORE OR LESS SPINNING IN PLACE. WHAT WILL ULTIMATELY HAPPEN
IS THAT THE RIDGE WILL FLATTEN BY SUNDAY BUT THEN RE-AMPLIFY ACROSS
THE WESTERN GREAT LAKES/UPPER MISSISSIPPI RIVER VALLEY INTO MONDAY
AS THE WESTERN TROUGH STARTS TO LIFT NORTHWARD. THE ECMWF REMAINS
SLOWER WITH THIS PROGRESSION THANKS TO A HIGHER AMPLITUDE TO THE
FEATURES WITH THE GFS A BIT FASTER AND PROBABLY STILL TOO FAST. BY
THE MIDDLE OF NEXT WEEK...THE RIDGING WILL BE PUSHING TO THE EAST
WITH A TROUGH MOVING INTO THE MIDDLE OF THE COUNTRY WITH ANOTHER
RIDGE WEST.
IN TERMS OF SENSIBLE WEATHER...MOSTLY SUNNY/CLEAR...WARM...AND DRY
CONDITIONS WILL BE THE RULE THROUGH MONDAY AND PROBABLY THROUGH
TUESDAY AT THIS POINT. TODAY MAY BE THE WARMEST DAY OF THIS WARM
STRETCH WITH AIRMASS MODIFYING/WARMING SLIGHTLY AND A STRONGER
SOUTHERLY BREEZE DEVELOPING THANKS TO THE TIGHTER PRESSURE GRADIENT.
HIGHS FOR MOST AREAS WILL BE EQUAL TO OR SLIGHTLY WARMER THAN
THURSDAY WITH LOW TO MID 80S...WITH COOLER HIGHS IN THE UPPER 70S
ALONG THE IMMEDIATE ILLINOIS SHORELINE OF LAKE MICHIGAN THANKS TO A
SLIGHT EASTERLY WIND COMPONENT. THE CORE OF WARMEST AIR WILL MOVE TO
THE EAST SATURDAY SO HIGHS WILL BE SIMILAR OR PERHAPS SLIGHTLY
COOLER THAN TODAY BUT A SOUTHERLY BREEZE MAY NEGATE ANY COOLING THAT
SLIGHTLY COOLER MID LEVEL TEMPS MAY PROVIDE. A MODEST COOLING TREND
MAY CONTINUE SUNDAY THROUGH TUESDAY WITH COOLER H85 TEMPS THAN WHAT
IS CURRENTLY IN PLACE. WILL KEEP THE FORECAST DRY THROUGH TUESDAY
WITH SLIGHT POPS TUESDAY NIGHT AND MARGINALLY HIGHER POPS TROUGH THE
REST OF THE WEEK AS THE RIDGE MOVES EAST ALLOWING THE WESTERN TROUGH
TO MOVE INTO THE REGION.
MDB
&&
.FIRE WEATHER...
323 AM CDT
DRY WEATHER WILL CONTINUE WITH HIGH PRESSURE STILL IN
CONTROL...BUT CENTERED TO THE EAST OF THE AREA. LOW PRESSURE WELL TO
THE NORTHWEST WILL HELP TO TIGHTEN THE PRESSURE GRADIENT TODAY
BRINGING AN INCREASE IN WINDS WITH HIGHEST GUSTS IN THE 20-25 MPH
RANGE...ESPECIALLY TOWARD THE INTERSTATE 39 CORRIDOR. SLIGHTLY
HIGHER DEWPOINTS MAY ADVECT IN THIS MORNING AS WINDS INCREASE BUT
AFTERNOON MIXING WILL LIKELY KNOCK THEM BACK A FEW DEGREES TO AROUND
50...OR EVEN UPPER 40S. THIS WILL RESULT IN RELATIVE HUMIDITY VALUES
OF AROUND 30 PERCENT WITH POTENTIAL FOR LOWER READINGS IF DRYING IS
A BIT MORE EXTENSIVE. SLIGHTLY HIGHER MOISTURE CONTENT AIR WILL MOVE
IN SATURDAY WITH TEMPERATURES SIMILAR TO TODAY YIELDING RH VALUES IN
THE LOWER 30 PERCENT RANGE.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTHERLY WIND GUSTS OF 20-25KT DURING THE AFTERNOON HOURS.
KREIN
//DISCUSSION...UPDATED 18Z...
A STRENGTHEN PRESSURE GRADIENT BETWEEN A TROUGH OF LOW PRESSURE TO
THE WEST AND HIGH PRESSURE TO THE EAST...COMBINED WITH AMPLE
SUNSHINE WILL ALLOW FOR SOUTHERLY WINDS TO GUST TO 20-25KT DURG
THE AFTERNOON HOURS. GUSTS HAVE BEEN A LITTLE SLOW TO DEVELOP OVER
NRN IL/NWRN IN...SO HAVE PUSHED BACK ONSET OF GUSTS TO 19Z.
GUSTINESS SHOULD SUBSIDE AT SUNSET...BUT PREVAILING SOUTHERLY
WINDS NEAR 10KT SHOULD PERSIST THROUGH THE NIGHT TONIGHT. A
SIMILAR SETUP IS LIKELY FOR TOMORROW WITH SOUTHERLY GUSTY WINDS
EXPECTED AGAIN.
OTHERWISE...WITH A STRONG RIDGE ALOFT OVER THE REGION...WEATHER
WILL BE DRY...WITH ONLY SOME CI FOR CLOUD COVER. NO PCPN IS EXPECTED
THROUGH THE PERIOD AND CIGS/VIS WILL BE UNOBSTRUCTED.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN ALL ELEMENTS.
KREIN/RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
* SATURDAY NIGHT THROUGH TUESDAY...VFR
* TUESDAY...CHANCE OF SHRA
* WEDNESDAY AND WEDNESDAY...CHANCE OF TSRA
SHEA
&&
.MARINE...
350 AM CDT
WITH A LARGE STRONG HIGH STILL IN PLACE S ACROSS THE HUDSON
VALLEY TO THE CAROLINAS AND LOW PRESSURE DEEPENING AS IT
CONTINUES TO ACCELERATE NORTHEASTWARD TODAY AND REACHING NORTHERN
MANITOBA OVERNIGHT THE STRONG PRESSURE GRADIENT PRESENTLY OVER THE
UPPER MS VALLEY SSW TO THE SOUTHERN PLAINS WILL ALSO SHIFT
NORTHEASTWARD OVER THE UPPER MIDWEST AND WESTERN ONTARIO. THIS
WILL KEEP THE STRONGEST WINDS TO THE NW AND N OF NORTHERN LAKE MI
LATER TODAY AND OVERNIGHT INTO SAT MORNING.
MODELS SHOW A LOW LEVEL SW FLOW OF 25 TO 35 KT SPREADING OVER
NORTHERN LAKE MICHIGAN TODAY...INCREASING TO 35 TO 45 KT TONIGHT.
THIS IS OCCURRING IN VERY WARM LOW LEVEL AIR AND WITH THE LAKE
SURFACE HAVING COOLED TO 12 TO 14C ACROSS CENTRAL AND NORTHERN
LAKE MI THERE WILL BE A SHALLOW BUT VERY STABLE LAYER IN PLACE.
THIS WILL SIGNIFICANTLY LIMIT MIXING OF THE STRONG WINDS ALL THE
WAY DOWN TO THE LAKE SURFACE.
WHILE THE UPWIND SHORES OF ESPECIALLY CENTRAL AND NORTHERN LAKE MI
WILL SEE STRONGER WINDS CARRYING OUT OVER THE WATER FROM WELL
MIXED LOW LEVELS OVER THE LAND TODAY...ANTICIPATE PREVAILING
WINDS TODAY AND TONIGHT TO REMAIN BELOW 30 KT N AND BELOW 25 KT S
DURING THE PERIOD FROM LATER TODAY INTO SATURDAY EVENING
AS THE LOW CONTINUES OFF ACROSS HUDSON BAY SAT THE PRESSURE
GRADIENT RELAXES AND SW TO S WINDS SLACKEN LATER SAT AND SAT
NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
