Category Archives: Forecast Discussion

Wednesday Morning Weather Brief…

Your complete weekly discussion can be found in the post below from last night, but here’s a recap of our current 7-day:

Screen Shot 2017-01-24 at 9.49.46 PMShowers will expand in overall coverage as we progress through the late morning hours, but shouldn’t amount to much (0.10″ for a few neighborhoods).  We return to a drier theme this afternoon.

10a forecast radar
10a forecast radar
11a forecast radar
11a forecast radar

A mild and windy afternoon is ahead, including gusts close to 40 MPH and highs in the lower-middle 50s.

Colder air will return tonight and remain in place through the second half of the work week, including the upcoming weekend.  Temperatures will grow cold enough Thursday morning for scattered snow showers.

Low-mid 30s Thursday morning
Low-mid 30s Thursday morning

Upper level energy will keep scattered snow showers going late week and on into the weekend.  Models can struggle on timing and specifics of the pieces of energy and we’ll keep an eye on things into the weekend.  Potential is present for a more “robust” clipper Sunday that could yield better coverage of steady snow showers.

gfs_namer_106_500_vort_ht_sLonger term, the GFS ensemble continues to show the cold growing deeper and stronger for the region as we progress into early February.  Winter is far from over.

gfs-ens_T2maMean_us_5

gfs-ens_T2maMean_us_8gfs-ens_T2maMean_us_10gfs-ens_T2maMean_us_12

No Comments Forecast Discussion, Forecast Models, Rain, snow, Unseasonably Cool Weather, Weather Rambles, Windy

Winter Returns…

January got off to a frigid start.  Remember this coast-to-coast cold, including sub-zero temperatures across central IN, during the first week of the month?

t0-1024x818After the past week to ten days, that frigid open to the month seems like forever ago!  The past 7-10 days has featured a significant January thaw, and temperatures now, MTD, are warmer than average across the Ohio Valley.  Warmest anomalies can be found across the southeast region.

conus_mtd_t2max_anom_2017That said, the pattern is shifting back to winter for the last week of the month and while the duration, longer-term, can be argued, the next 2-3 weeks appear to offer an opportunity to play “catch up” in both the snow and cold departments.  Note the developing eastern troughiness.  This will bring colder air back into the east as we close January and open February.  The GFS ensembles, courtesy of Tropicaltidbits.com, also develops an interesting “blocky” look towards the end of the period in Week 2.  Should this verify, it would lead to a better chance of the cold, active pattern locking in.

GEFS2wk12417
You’re corresponding temperature anomalies show the shift back to a colder than normal regime.

Days 2-6
Days 2-6
Days 4-8
Days 4-8
Days 6-10
Days 6-10
Days 12-16
Days 12-16

A fast northwest flow will also result in multiple “pieces” of energy rotating southeast and we’ll forecast a period of snow showers by mid and late week, continuing into the weekend.  There’s the chance of a stronger clipper system sometime in the Sunday-Tuesday time frame that we’ll have to keep a close eye on.  We want to stress that global modeling will struggle with the specifics (timing and strength) of these clipper systems until within a couple days.

Longer term, while confidence is high on the evolution to a cold, wintry regime through the medium range, the longevity and sustainability of the cold is in question.  For instance, by Day 10 (as the GFS continues to drill cold into the region), the European ensembles are much less impressed and suggest the overall transient pattern we’ve dealt with for the balance of the winter continues:

ecmwf-ens_z500aNorm_namer_11

ecmwf-ens_T850a_namer_11Thinking here at IndyWx.com believes the European is likely rushing the warmer central look.  Time will tell…

**We do note the NEW European Weeklies lock a period of cold into the east from mid-February through early March, including a stormy (snowy) look.  Will Old Man Winter have the final say?

Updated 7-day later this evening!

No Comments Ensemble Discussion, Forecast Discussion, Forecast Models, January Thaw, snow, Unseasonably Cool Weather, Unseasonably Warm, Weather Rambles

Times Are Changing, Or Are They?

January-to-date is running milder than normal across the region- to the tune of 3.3 degrees (F).  This is after a frigid open to the month, as you recall.

conus_mtd_t2max_anom_2017The second week of the month warmed significantly and continues, overall, for the next week.

ncep_cfsr_noram_t2m_week_anomThe mid-January warmth is attributed to a roaring PAC jet which is currently helping flood the country with temperatures much more like spring than the dead of winter.  We continue to forecast 60+ this weekend across central IN.

Winter lovers, have no fear as changes appear to be in the offing as we go through the last few days of January and head into February.  The winter so far has featured conflicting signals that continue to try and compete with one another to take hold of the pattern.  Can we get these drivers to align in a way that would pull a more persistent trough into the east for the second half of the winter and, ultimately, set-up a sustained cold pattern helping make up for lost time in the snowfall department?  Time will tell, but we do note the following late month:

  • (+) PNA pattern
  • Sudden stratospheric warming event
  • High latitude blocking

All are encouraging for a shift back towards a wintry regime.  As always, the devil is in the details and we’re skeptical as to the longevity of these signals.  “Cautiously optimistic” would be the way to sum up our current feel longer-term into the month of February, but we’re not as bullish on lock and hold cold, wintry conditions at this time as what you may hear from some of our national compadres.  Understanding that various drivers can have a different impact mid and late winter as opposed to early is one thing.  It’s also important to note that long term modeling has been abysmal as of late and we want to tread through the next couple of weeks with caution to see whether or not the cold drivers can finally take hold.

Needless to say, at least through late month, one can see the significant changes take place at 500mb.

Thursday:

ecm_eps_z500a_noram_2This Weekend:

ecm_eps_z500a_noram_5Next Thursday:

ecm_eps_z500a_noram_9Next Weekend:

ecm_eps_z500a_noram_11The pattern begins in the short-term with a look that will power anomalous warmth through the weekend, along with renewed rain chances Thursday night into Friday (another 1″+ for most), but begins to shift next week towards the colder look.  The 2nd (weekend) storm system will be significant and poses a severe risk to the southeast region.  Modeling has backed away on the heavy rain threat Sunday, but showers will be around early next week along with very windy conditions (40+ MPH gusts).  Blocking is forcing the low south.  By the time we get to next weekend, the pattern has done a 180 and in a position to drill unseasonably cold air back into the central and eastern portions of the country.

As far as storms go later in the period, it’s far too early to discuss specifics, but the pattern seems to be one that will promote the chance to get into the act on high-ratio producing clippers.  It’s the first time we can say that this year.  Time will tell…

No Comments 10-day, Arctic Cold, Forecast Discussion, Forecast Models, Heavy Rain, High-latitude Blocking, PNA, snow, Spring Tease, Unseasonably Cool Weather, Unseasonably Warm, Windy

Sunday Afternoon Rambles…

1.) January, month-to-date, is running slightly above normal at IND (+1.2 F) and nearly 1″ above normal in the precipitation department.  Keeping true to the winter, overall, greatest cold departures are centered over the northern Plains and northern Rockies.

conus_mtd_t2max_anom_20172.)  Showers will creep north overnight into Monday morning, but shouldn’t amount to much.  They will be scattered in nature across central Indiana.

hrrr_ref_indy_183.)  More widespread rain and embedded thunder will develop Monday night into Tuesday morning.  This should amount of widespread half inch to one inch totals across the viewing area.

hires_ref_indy_37

hires_ref_indy_404.)  A moist southwest flow will help push a warmer regime northward for the second half of the week.  Though warm, we’ll also have to deal with periods of rain as disturbances track northeast.  We circle Friday and Sunday as the wettest days and remain optimistic Saturday will feature dry and unseasonably warm conditions (lower-middle 60s).  Between the rainy days Friday and Sunday, additional rainfall totals of 1″-2″ seem like a good bet.

SW Flow

D75.)  The evolution of the pattern just beyond the 7-day period we’ll begin to take on an increasingly wintry look and we remain confident on a flip back to wintry conditions as we roll through the last week of the month.  We’ll have to keep a close eye on a storm system in the 8-10 day period.  It’s obviously way too early to discuss specifics, but this will be the time the pattern is beginning to turn back towards a wintry regime…

ecm_eps_z500a_noram_11

 

No Comments 7-Day Outlook, Forecast, Forecast Discussion, Forecast Models, Heavy Rain, Unseasonably Warm, Winter thoughts...