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 08Z...
* NO CONCERNS OVERNIGHT
* GUSTY SOUTH WINDS IN THE AFTERNOON
SHEA
//DISCUSSION...UPDATED 06Z...
SURFACE RIDGING TO THE EAST ACROSS THE OHIO VALLEY...COUPLED WITH
LOW PRESSURE ACROSS THE PLAINS...IS ALLOWING FOR LIGHT GRADIENT
FLOW FROM THE SOUTH. GRADIENT WILL TIGHTEN IN THE DAYTIME AND
ALLOW SOME OF THE HIGHER MOMENTUM AIR ALOFT TO MIX DOWN. THE
TIGHTER GRADIENT AND STRONGER WINDS EXPECTED TO REMAIN WEST AND
ACROSS THE MISSISSIPPI RIVER VALLEY. FORECAST SOUNDINGS SUGGEST
PEAK GUSTS IN THE AFTERNOON IN THE MID TEENS FOR ORD/MDW...WHILE
RFD WILL LIKELY REACH THE LOWER 20 KT RANGE. ATMOSPHERE WILL AGAIN
DECOUPLE AFTER SUNSET ALLOWING WINDS TO AGAIN WEAKEN TO THE 6-9 KT
RANGE OUT OF THE SSE OVERNIGHT.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 08Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
SHEA
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY THROUGH MONDAY...VFR.
TUESDAY AND WEDNESDAY...CHANCE OF SHRA.
&&
.MARINE...
352 PM CDT
A LARGE HIGH STRETCHING FROM QUEBEC THROUGH NORTH CAROLINA WILL
BEGIN TO SETTLE SOUTH TO OVER THE MID ATLANTIC COAST THURSDAY
NIGHT. A DEEPENING LOW PRESSURE SYSTEM CURRENTLY OVER SOUTHERN
WYOMING WILL MOVE NORTHEASTWARD INTO MANITOBA BY SATURDAY MORNING AND
DEEPEN. THE LOW WILL THEN CONTINUE NORTHEASTWARD TO OVER HUDSON
BAY BY SATURDAY EVENING. THE MOVEMENT OF THE LOW WILL STRENGTHEN
THE PRESSURE GRADIENT OVER THE CENTRAL AND NORTHERN SECTIONS OF
LAKE MICHIGAN FRIDAY NIGHT...RESULTING IN WINDS OVER THE NORTHERN
HALF OF LAKE MICHIGAN INCREASING TO 20-25 KT. THE WARM LAKE
TEMPERATURES AND WARM AIRMASS OVERHEAD WILL CREATE STABLE
CONDITIONS...THEREFORE STRONGER WINDS WILL NOT BE ABLE TO MIX DOWN
TO THE LAKE SURFACE. WIND GUSTS WILL BE MINIMAL AT BEST FRIDAY AND
SATURDAY. WINDS WILL WEAKEN LATE ON SATURDAY AS THE LOW MOVES OVER
THE HUDSON BAY AND THE PRESSURE GRADIENT WEAKENS.
OTHERWISE...HIGH PRESSURE AND LIGHT FLOW WILL DOMINATE THE
PATTERN FOR THE EASTERN HALF OF THE UNITED STATES THROUGH THE
BEGINNING OF NEXT WEEK.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
