Category: GFS

Jan 27

Keeping An Eye On The Weekend…

Forecast models have been printing out wintry solutions for the upcoming weekend- particularly Saturday night through Super Bowl Sunday.

The GFS 500mb charts between 12z Monday and this morning show the key with this potential storm.  Note the difference between yesterday (top) and today (bottom).  The GFS model brings more energy out and the result is a stronger storm system.

SunGFS5001

 

GFSSun5002Timing between cold and moisture associated with storm systems has been the important missing link this winter with bigger storms.  Does that trend continue this weekend?  Snow lovers hope not…

A key ingredient that has been missing in the past is a big area of high pressure north of the region supplying cold air as surface low pressure tracks in a favorable position for wintry precipitation.  Models do suggest not only renewed arctic high pressure building down the Plains region Sunday into Monday, but also a 1040mb high over the northern Lakes region.  This would help go a long way in keeping cold air flowing into the region.

What about the sensible weather here?!  Keeping in mind that this is still an event 5 days out…..  The GFS model suggests mostly a snow event north-central, but also brings in a wintry mix of icy precipitation and rain across the southern half of the state.  The Canadian forecast model (not shown here) is more suppressed and leads to an accumulating weekend snow event across the region and targets southern portions of the state for heaviest snowfall.  The European model is the most “ideal” scenario for central Indiana snow lovers and leads to a significant snow event across the heart of the state.

Note the European forecast model track a wave of low pressure in an ideal location for heavy snow across central Indiana before intensifying and hammering the Northeast region.

ecm_mslp_east_7

 

ecm_mslp_east_8

We’ll continue to keep a close eye on this developing situation. Stay tuned….

Permanent link to this article: https://indywx.com/2015/01/27/keeping-an-eye-on-the-weekend/

Jan 22

Step Down Process To Cold Before The Return Of Truly Frigid Times…

The past 5-7 days have featured a common “January thaw-” something typically seen in even the coldest Januarys.  The coming 5-7 days will see a “step down” process of colder weather, interrupted by a day or two of milder southwest breezes.  In the longer range, we hold firm on the idea of more sustained cold, and potentially frigid air, setting up shop to open February.

See the GFS track the clipper through the lower lakes this weekend.  This is a mild track for central Indiana and will keep the accumulating snows over the Lakes region, extending into northern portions of the state.  Some light snow will fly here late Sunday night/ early Monday, but accumulations should be minimal.

gfs_ptype_slp_conus2_12

gfs_ptype_slp_conus2_16A brief surge of arctic air will invade early next week and may be accompanied by light snow Tuesday.

gfs_ptype_slp_conus2_21A brief southwesterly flow will allow milder air into the region by the middle of next week, but we caution this will be brief.

gfs_ptype_slp_conus2_29Much colder times loom to open February, potentially with a winter storm.  Obviously with this being in the 8-10 day period, there will be a lot of time to watch the storm potential.  Models have struggled mightily with storms this winter so far.  We’re much more confident on the cold, and potentially downright frigid air at that (still don’t think we’ve seen the coldest air of the winter yet).  Note the GFS sees the arctic highs “lining up.”

gfs_ptype_slp_conus2_41The European ensembles and operational are also keying in on the cold and wintry pattern closing January and to open February:

Geopotential32at32500hPa_North32America_216Initially the cold attacks the northeastern portions of the country, but “backs” west with time in the longer range:

Days 5-10

1Days 10-15

2The NAEFS and CFSv2 see the colder pattern returning:

2015012212_054@007_E1_north@america_I_NAEFS@TEMPERATURE_anomaly@probability@combined@week2_186

wk1.wk2_20150122.NAsfcT

We still think there’s a lot of “winter” left in the coming months.  Many folks enjoy snow Christmas into January, but begin to crave spring in February and March.  This is the type pattern that can be quite “ugly” for spring lovers as colder and snowy weather can push well into the spring months…  (Noted that we still have a lot of catch up to do in the snow department, but we’re not ready to say we won’t make up for “lost time”).

Permanent link to this article: https://indywx.com/2015/01/22/step-down-process-to-cold-before-the-return-of-truly-frigid-times/

Jan 16

Friday Morning Thoughts…

I’m blessed to have family in town this weekend so posts will be a bit off schedule the next few days, but keep it tuned here as they will come!

What a remarkable January this is as temperatures are averaging more than 9 degrees (fahrenheit) below average AND COLDER than last January.  While I know snow lovers are wanting more snow (yours truly included), one has to sit back and really appreciate the pattern for what it is from a cold standpoint.  I would go as far as to argue this pattern is actually more impressive than last January as the cold has come in the face of what’s been a much less impressive snow pack (for the most part).

ncep_cfsr_noram_t2m_anom

Despite a brief “relaxation” now, models suggest the cold comes on like gangbusters yet again to wrap up the month.  Given where we’ve been and what appears to lie ahead, it would seem as if this January will be even colder than last January- not only through the first half, but at month’s end.  It’ll be fascinating to watch unfold.

Speaking of snow, I still believe this is the type pattern that can “flip on a dime” in the snow department.  The sea surface temperature profile and analogs at least suggest we’re on the playing field for a stormy ride through the month of February and even into March this year.  Does it mean it has to be a snowy pattern?  No, but at this distance it’s at least nice knowing we’re on the field with a chance to win the game.

In the shorter term, a windy “mild up” will occur Saturday as highs reach the middle to upper 40s with a gusty southwest wind in play.  Winds will top 30-40 MPH so you’ll definitely want to “batten down the hatches” Saturday.

gfs_ptype_slp_conus2_7

Permanent link to this article: https://indywx.com/2015/01/16/friday-morning-thoughts/

Jan 14

Relatively Quiet Now, But It Won’t Last Long…

Enjoy our relatively quiet and briefly milder weather pattern as mid and long range guidance suggests we reload the cold with authority and associated wintry precipitation threats…

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Permanent link to this article: https://indywx.com/2015/01/14/relatively-quiet-now-but-it-wont-last-long/

Jan 01

Lots Of Winter Next Week….

Quick post during halftime of the Auburn/ Wisconsin game (WAR EAGLE)!!! A full 7-day forecast will be posted later tonight. Just wanted to touch on the bitter shot of air…

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Permanent link to this article: https://indywx.com/2015/01/01/lots-of-winter-next-week/

Dec 31

Brrrrr…. Cold Pattern Continues

Many across the Lower 48 are running MUCH colder than average this morning. Take a look a temperature departures from normal this morning: Mind you this is in the face…

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Permanent link to this article: https://indywx.com/2014/12/31/brrrrr-cold-pattern-continues/

Dec 15

Monday Morning Rambles…

1.) Rain will spread into the state later this afternoon. Most folks will see 0.25″-0.50″. 2.) Colder air will filter into the region by the mid week period and help…

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Permanent link to this article: https://indywx.com/2014/12/15/monday-morning-rambles/

Dec 11

“I’m Dreaming Of A White Christmas…”

Modeling continues to suggest a cold and wintry time lies ahead as we progress into and through the special Christmas period. Could this be the scene across central Indiana Christmas…

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Permanent link to this article: https://indywx.com/2014/12/11/im-dreaming-of-a-white-christmas/

Dec 09

A Look At Where We’ve Been And Where We’re Going…

December so far has been a battle between the cold northern tier and warmth south. The so-called “battle zone” has been located over our neck of the woods and lead…

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Permanent link to this article: https://indywx.com/2014/12/09/a-look-at-where-weve-been-and-where-were-going-4/

Dec 04

Short-term Cold; Mid-range Warm…

There’s been a ton of conversation as of late about where this overall weather pattern is heading.  Perhaps it’s the Christmas season that brings out the conversation as everyone is hoping for that cold pattern to provide a White Christmas.

While in the short-term cold will continue to dominate, we’re becoming increasingly confident of an unseasonably mild stretch of air in the mid-range period.  That’ll take us up to the week before Christmas…

In the short-term, the positive PNA will continue to be the primary driver in our pattern.  This will ensure a colder east through the majority of week 1 (through next Friday).

pna.sprd2

A positive PNA pattern typically leads to below normal heights (trough) and associated cooler than normal pattern across the eastern region.

A positive PNA pattern typically leads to below normal heights (trough) and associated cooler than normal pattern across the eastern region.

Modeling sees the cool east in week 1 and warm west- typical of a positive PNA pattern:

gefs_t2anom_by5_conus_29

There are changes in the mid-range period that’ll have lovers of winter and cold frowning.  Many of our long-term readers know how we use the “typhoon rule” as a good indication of what we can expect across our region 6-10 days down the road.  As stated multiple times in the past (want to give credit where credit is due), we learned this from the great Joe Bastardi.  For those that are new here, I’ll describe this very briefly (you can read through the archives, if you’d like, for a longer/ more detailed description).  Typically when you have a recurving typhoon in the WPAC, that suggests a trough (colder pattern) across the central and eastern Lower 48.  On the flip side, when you have a westward moving typhoon, that’s a good indication of eastern ridging (warmer pattern).

Courtesy of the Joint Typhoon Warning Center, Super Typhoon Hagupit is forecast to move on a general westward trajectory.

wp2214

This is a very good sign of a much milder than normal period in the mid-range (days 8-12).  Modeling, in return, is going towards a warm pattern (associated ridge) week 2:

test8

The GFS ensembles and NAEFS agree on the warmth and given what we’ve discussed above, so do we:

2014120412_054@007_E1_north@america_I_NAEFS@TEMPERATURE_anomaly@probability@combined@week2_186

D12

In fact, it wouldn’t surprise us to see high temperatures in the 55-60 degree range during a day or two week 2.

Really quick and before we end- lovers of winter weather, there’s absolutely NO reason to throw in the towel.  In fact, indications in the long range suggest the trough collapses into the east during the week leading up to Christmas and that could provide for all sorts of wintry “mischief” when almost all of folks are wanting snow…

Much more on that in the days ahead.  Have a great night!

Permanent link to this article: https://indywx.com/2014/12/04/short-term-cold-mid-range-warm/

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