Jump to content
  • Member Statistics

    17,609
    Total Members
    7,904
    Most Online
    NH8550
    Newest Member
    NH8550
    Joined

January 17-19th Plains/MW/Lakes Storm Potential


A-L-E-K

Recommended Posts

  • Replies 1k
  • Created
  • Last Reply

DVN

THE SYSTEM SUNDAY NIGHT THROUGH MONDAY EVENING CARRIES A ITS MOST

SIGNIFICANT QUESTION ON SATURATION DURING THE WAA PROCESS. THE

GFS...GEM...NAM...00Z EC...AND UKMET ALL SATURATE FOR SNOW ON THE

WAA WING...AND THIS SEEMS THE MOST LIKELY SCENARIO. FOR OUR

CWA...THIS MEANS A BOUT OF MODERATE FORCING...AND WITH STRONG

BAROCLINICITY...A PERIOD OF MODERATE SNOW IS LIKELY. AMOUNTS

CONTINUE TO APPEAR TO RANGE FROM 1 TO 3 INCHES CONSERVATIVELY...TO 2

TO 6 MORE AGGRESSIVELY. THIS WILL ALL DEPEND ON THE SPEED OF

SATURATION IN THE WAA. I DO FEEL MODELS ARE OVER DONE ON THE WARMING

AT THE SURFACE GIVEN THE COLD START SUNDAY...AND INITIAL DELAYED

SATURATION. SATURATION PROCESS AND LIFT SHOULD COOL TEMPS ALOFT

SLIGHTLY AND KEEP MOST PCPN AS SNOW...THOUGH A MIX OF SLEET AND SNOW

SOUTH SEEMS POSSIBLE. AN ADVISORY REMAINS THE MOST LIKELY HEADLINE

FOR THIS EVENT...IF ONE IS IN FACT NEEDED.

Link to comment
Share on other sites

This is gonna sound a little silly but here's my best guess on ptype for us. Snow, freezing rain, or rain, changing to rain then changing to snow. I guess you can't rule out a little zr between the last transition but probably not very likely. Overall amounts should be pretty light.

Not silly, I think you have it nailed. Kitchen sink weak slop-fest.

Link to comment
Share on other sites

nicely done AFD by Gino

ATTENTION WILL THEN TURN TO THE SYSTEM CURRENTLY OFF THE BRITISH

COLUMBIA COAST...PROGGED TO MAKE LAND TONIGHT BEFORE RIDING THE

NORTHWEST FLOW INTO THE NORTH CENTRAL CONUS. MODELS ARE GENERALLY IN

GOOD AGREEMENT ON AMPLIFYING THE SHORTWAVE A BIT AS IT EMERGES EAST

OF THE ROCKIES AND EVEN IN PRETTY GOOD AGREEMENT ALOFT ON THE

TIMING/AMPLITUDE OF THE SHORTWAVE AS IT TRAVERSES THE WESTERN GREAT

LAKES MONDAY INTO MONDAY NIGHT. MOST NOTABLE DIFFERENCES AMONG THE

MODELS IS WITH RESPECT TO THE TRACK OF THE SURFACE LOW...WHICH WILL

BE KEY TO PRECIP TYPE AND AMOUNTS FOR OUR CWA.

THE 12Z RUNS OF THE GFS/UKMET CURRENTLY ACCOUNT FOR THE SOUTHERN

MOST TRACK OF THE SFC LOW...WITH THE 12Z WRF-NAM THE NORTHERN MOST.

THE 12Z ECMWF SEEMS TO OFFER UP A GOOD COMPROMISE BETWEEN THE TWO

EXTREMES AND IS SUPPORTED BY THE 15Z SREF AND 12Z GFS ENSEMBLES.

REGARDLESS OF THE EXACT TRACK...ALL GUIDANCE SUGGESTS THAT OUR

ENTIRE CWA WILL MAKE IT INTO THE WARM SECTOR WITH VERY STRONG WARM

AIR ADVECTION AIDED BY 50KT+ H8 JET AND STRONG SOUTHERN WINDS AT THE

SURFACE LIKELY TO RESULT IN A RAPID RECOVERY IN TEMPS FROM THEIR

CURRENT STATE.

FORECAST SOUNDINGS FROM VIRTUALLY EVERY MODEL I CAN FIND WOULD

CONTINUE TO SUPPORT AN ALL SNOW EVENT FOR ALL BUT THE EXTREME

SOUTHERN MOST CWA. GIVEN THE FORECAST TRACK OF THE SFC LOW AND PAST

EXPERIENCE WITH MODEL GUIDANCE UNDERESTIMATING THE STRENGTH OF

STRONG WARM AIR ADVECTION HAVE OPTED TO INTRODUCE A MIX OF

SNOW/SLEET/FRZ RAIN INTO THE FORECAST FOR MOST OF THE AREA MON

AFTERNOON/EVENING...AND EVEN INCLUDED A CHANCE OF RAIN SOUTHERN CWA.

GIVEN THE TREND OF THE MODELS TO TRACK THE SFC LOW FARTHER NORTH AND

THE ROBUSTNESS OF THE PROGGED WARM AIR ADVECTION (ECMWF BRINGING 2M

TDS INTO THE MID 30S) THINK ITS POSSIBLE THAT P-TYPE COULD

TRANSITION TO A PERIOD OF ALL RAIN AS FAR NORTH AS CHICAGO...BUT FOR

NOW ONLY WANTED TO MAKE LARGE BABY STEPS TOWARD A LESS WHITE/MORE

WET SOLUTION. DESPITE THIS TREND WILL CONTINUE HIGHLIGHT THE

POTENTIAL FOR SOME SNOW ACCUMULATION NORTHERN CWA AND A PERIOD OF

ICY ACCUM POSSIBLE ELSEWHERE MONDAY.

Link to comment
Share on other sites

MKX

EARLY ON...FOCUS OF BEST ISENTROPIC LIFT STAYS TO THE WEST OF THE

REGION SUNDAY EVENING...THEN WEAKENS AS IT SPREADS EAST OVERNIGHT.

TIGHTENED POP GRADIENT AFTER 06Z MONDAY...WITH HIGHER THAN PREVIOUS

FORECAST IN WEST BUT LOWER IN THE EAST...PRIOR TO 12Z. INCREASE

CHANCES RAPIDLY TO CATEGORICAL POPS BY MONDAY AFTERNOON WITH STRONG

LAYER Q-VECTOR CONVERGENCE IN 850-700MB WAA AHEAD OF SHORT WAVE

AXIS. WILL KEEP LIKELY POPS IN THE EAST MONDAY EVENING UNTIL TROUGH

AXIS PUSHES THROUGH.

WAA REGIME WILL WARM COLUMN SO SNOW/LIQUID RATIOS FROM ROBBER

FAVORING TOWARD THE LOWER END OF A 9:1 TO 15:1 RANGE...AND COBB

AVERAGING AROUND 12:1 LOOK ON TRACK. STORM TOTAL QPF BETWEEN 0.2 AND

0.3 YIELDS 3 TO 4 INCHES OF SNOW.

THE WAA WILL ALSO BRING A NON-DIURNAL TREND TO SURFACE TEMPERATURES

SUNDAY NIGHT WITH SLOW WARMING AFTER 06Z...AND AGAIN MONDAY AND

MONDAY NIGHT. PERSISTENT WAA WILL WARM TEMPS THROUGH THE DAY WITH

HIGHS BETWEEN 3 PM AND 6 PM...THEN STEADY UNTIL MIDNIGHT WITH TEMPS

COOLING BEHIND SURFACE FRONT. AMOUNT OF WARMING AND COOLING

DEPENDENT ON LOW TRACK SO A BLEND OF TEMPERATURES USED.

Link to comment
Share on other sites

DVN

LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY

SUNDAY NIGHT THROUGH TUESDAY...IN HANDLING OF THE PACIFIC RIDGE-

RIDING WAVE ENERGY THE 12Z MODEL RUNS HAVE COME CLOSER TOGETHER IN

SPEED AND HANDLING OF UPPER LEVEL FEATURES...BUT STILL SOME

DIFFERENCES IN LOWER LEVEL MOISTURE AND LOW PROGRESSION TO IRON

OUT OVER THE NEXT 12 HRS OR SO. IN GENERAL...THE 12Z NAM IS THE

FURTHEST NORTH WITH LOWER LEVEL LOW PROGRESSION AND THUS MORE ROBUST

WITH WAA AHEAD OF IT THROUGH THE LOCAL FCST AREA...BUILDING A WARM-

WEDGE ALOFT DEEP ENOUGH FOR A MIX OF SLEET AND SWITCHING TO FREEZING

RAIN ACRS AT LEAST THE SOUTH HALF OF THE FCST AREA BY MON AFTERNOON.

THE NAM MAY EVEN WARM ENOUGH TO THE SFC FOR ALL RAIN IN SOUTHEAST

IA AND WEST CENTRAL IL...WITH A DECENT FREEZING RAIN EVENT ALONG THE

I80 CORRIDOR. THE 12Z GFS IS SLOWER AND FURTHER SOUTH...MAKING FOR

MAINLY A SNOW EVENT FOR MOST OF THE CWA THROUGH MON EVENING

/WIDESPREAD 1-3+ INCHES CWA-WIDE WITH AREAS OF 3 TO 4.5 INCHES IN THE

NORTHEAST THIRD OF THE CWA/ WITH MAYBE SOME SLEET IN THE FAR SOUTH

MON AFTERNOON AND EVENING. FOR NOW...WILL SIDE WITH THE NEW 12Z RUN

ECMWF WHICH IS TRENDING WITH A FASTER INCOMING SPEED AND LOW

PLACEMENT IN BETWEEN THE GFS AND NAM...ALTHOUGH IT HAS TRENDED CLOSER

TO THE NAM. THUS WITH FASTER INCOMING SPEED...WILL INCREASE POPS FROM

06Z-12Z MON ACRS THE NORTHWEST HALF OF THE CWA. DESPITE SIGNALS OF A

ROBUST PRE-SYSTEM WAA WING OF LIFT...AGREE WITH THE PREVIOUS SHIFT/S

CONCERN OF SPEED OF SATURATION AND EXTENT OF THE LOW TO MID LEVEL OF

THE COLUMN THAT NEEDS TO MOISTEN BEFORE PRECIP SFC ARRIVAL. EVEN

TAKING THIS INTO ACCOUNT...THERMODYNAMIC PROFILES SUGGEST ENOUGH

SATURATION FOR LIGHT TO BOUTS OF MODERATE SNOW BY MON MORNING

ESPECIALLY ACRS THE NORTHEAST HALF OF THE DVN CWA. BULK OF

ACCUMULATING SNOW WILL LOOK TO FALL FROM 10Z MON...TO 00Z TUE WITH

EVEN MORE CONCENTRATED WINDOWS DUE TO CONVERGENT WAA BANDING WITHIN

THAT TIME-FRAME. STILL APPEARS A SOLID 3-4+ INCHES OF SNOW ACCUM

ALONG AND NORTH OF A LINE FROM VAN HORNE IA...TO CLINTON IA AND TO

SOUTH OF STERLING IL AND WORTHY OF AN ADVISORY AND ONGOING SNOW

TOTALS STILL LOOK ON TARGET IN THESE AREAS. BUT WITH THE 12Z ECMWF

HANDLING AND FURTHER NORTH PROPAGATION...WILL EXPAND SNOW AND SLEET

MIX FURTHER NORTH TO AT LEAST THE I80 CORRIDOR. WILL HOLD OFF OF

FREEZING RAIN MENTION FOR NOW...BUT ANY FURTHER NORTH TRACK OF THE

ACCEPTED MODEL SOLUTION OR SIGNALS OF EVEN STRONGER WAA AHEAD OF THE

CURRENT MODEL TRACK WILL WARRANT ZR MENTION BY MIDDAY MONDAY FOR THE

SOUTH THIRD TO POSSIBLY HALF OF THE LOCAL FCST AREA. AGAIN THE SFC

MAY WARM ENOUGH FOR ALL RAIN IN THE SOUTHERN THIRD/HWY 34 AND SOUTH

BY MON AFTERNOON WITH STRONGER BOUNDARY LAYER WAA. SLEET MIX AND

LOWER LSR/S WILL KNOCK DOWN SNOW ACCUMULATION POTENTIAL SOUTH OF I80

TO AROUND 1 TO 2 INCHES...PROBABLY CLOSER TO THE 1 INCH TOTAL. THE

ACCUMULATING PRECIP WILL PROBABLY EXIT OUT OF THE CWA FASTER THAN

CURRENTLY PROGGED...BUT WILL KEEP MENTIONABLE CHC POPS FOR MON

EVENING ESPECIALLY ACRS THE EAST. TOP-DOWN DRYING WITH LINGERING LIFT

MAY LEAD TO FREEZING DRIZZLE BY MID EVENING MON NIGHT. BRISK PRE-

FRONTAL SOUTH TO SOUTHEAST SFC WINDS MAY PRODUCE SOME

DRIFTING/BLOWING MON AFTERNOON IN AREAS RECEIVING 2+ INCHES.

Link to comment
Share on other sites

This storm threat just looks like junk. It took two bad turns as of late. First, no full phase with the Canadian vortex. Second, the leading S/W is junk. The resultant storm is pretty weak and not all that organized. ECM may not have had the track perfect, but it was pretty consistently the weakest of all guidance.

Link to comment
Share on other sites

18z NAM does have .25-.50 liquid for N IL to. 3-5 inches for S WI/N IL. How is temperatures for ORD throughout event?

I believe the 18z NAM was warmer for here than the 18z GFS is, we would have more mixing/rain problems if that run of the NAM verified. The GFS run is a mostly if not all snow run for here, possible mixing at the end.

Link to comment
Share on other sites

This storm threat just looks like junk. It took two bad turns as of late. First, no full phase with the Canadian vortex. Second, the leading S/W is junk. The resultant storm is pretty weak and not all that organized. ECM may not have had the track perfect, but it was pretty consistently the weakest of all guidance.

Yeah as far as the long rang was concerned, the ECM had the right idea.

Link to comment
Share on other sites

Looks like it may be bon voyage to our snowpack again down here in central Indiana. Euro has the 40º line getting awfully close to LAF, and 12z MEX has a high of 37º for Tuesday. Taking into account how the models typically underestimate WAA, I'm liking a high somewhere in the low 40's here early Tuesday before temps begin to dip down again. In conjunction with the rainfall= :frostymelt::thumbsdown:

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...