Category: Forecast Models

Sep 12

Tracking Two Fronts This Week…

It’s a quiet and cool start to the work week across central Indiana.  In fact, a couple upper 40s are showing up on the morning station plots.  It’s getting to be that time of the year…  (Feel free to click on the image to enlarge).

screen-shot-2016-09-12-at-7-35-53-amTemperatures are running slightly below average, locally, with cooler anomalies across the Northeast.

screen-shot-2016-09-12-at-7-37-20-amHigh pressure will remain entrenched over our region today and supply dry conditions and pleasant humidity levels.

gfs_mslp_pcpn_frzn_us_1Our next storm system will push in Wednesday and as the cold front sags south through the state, it will spark scattered showers and possibly a thunderstorm.

gfs_mslp_pcpn_frzn_us_10Reinforcing cool air will move in behind the front for a couple days.  Lows in the lower-middle 50s with highs in the upper 70s.

3As we flip the page to the weekend, it still looks rather damp Saturday as another boundary moves in.  This will have more moisture to work with when compared to Wednesday and rain coverage will be more widespread.  As a whole, (7) day rainfall totals should be in the 0.50″-1.00″ range for most.

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Permanent link to this article: https://indywx.com/tracking-two-fronts-this-week/

Sep 08

Periods Of Heavy Rain Then Much Cooler…

A “wavy” frontal boundary will be located over our region through the next 36-48 hours before getting a “shove” south from a cold front Saturday. 


The combination of the stationary front along with a tropical-rich air mass in place will be enough in and of itself to produce periods of heavy rain today into Saturday morning. Add in a couple of disturbances moving along the boundary and the heavy rain prospects grow even higher. A strong to severe storm also can’t be ruled out-primarily this afternoon and again Friday afternoon. 

Already this morning (6:30a) we note widespread showers and embedded thunder impacting IL and northern IN. 


As mentioned, the air mass is plenty “juicy” to fuel locally heavy rain through the period. Precipitable water values (PWATs) will surge north of 2″ for all of central IN later today. 


While it won’t rain the entire time, periods of heavy rain will remain in our forecast today through Saturday morning. Widespread 1″-2″ totals will be common, with locally heavier totals. 


High pressure will build overhead Sunday and lead to quite the change. A much cooler and drier air mass will return along with brighter skies to wrap up the weekend. 


Lows in the middle 50s will be common for the city, itself, Sunday through Tuesday mornings. Upper 40s to lower 50s are a good bet away from the metro. 

Permanent link to this article: https://indywx.com/periods-of-heavy-rain-then-much-cooler/

Sep 06

Tuesday Evening Weather Notebook…

It’s been a cool and dry start to the month of September. Through the first few days, IND is running 0.70° below normal and 0.44″ below average precipitation. 


The upper ridge currently in place will deliver more late summer heat through the end of the work week. It’ll remain mostly dry, as well. 


Much better rain and storm chances will have to be built into our forecast Friday into Saturday, courtesy of a cold front moving into the region. 


A much cooler regime will settle into the region over the weekend. Highs behind the front in the 70s with lows in the 50s will be common- after rain potential of 1″-1.5″ for most. 


A reinforcing shot of cool air will arrive the middle of the following week. Early indications suggest the second shot of fall-like air will be even cooler than this weekends’ and could feature widespread 40s at night. 

Permanent link to this article: https://indywx.com/tuesday-evening-weather-notebook/

Sep 04

New SST CA Model Weighs In On Winter…

The updated Sea Surface Temperature Constructed Analog model is in for the winter. In short, it suggests a slow start to winter gains momentum and turns much colder as mid and late winter arrive. It’s also a stormy look, locally, and would imply big-hitter potential in the Ohio Valley.

500mb pattern

*Note how the trough becomes more established over the central and east during the January through March period. 

Temperature anomalies


The consistency is remarkable on the bullish cold signal for the central and east for the January-March time frame. We note high agreement, month-over-month, on the J-M time frame being significantly cold. 

Precipitation anomalies

*No doubt a stormy signal through the Ohio Valley.

Time is ticking…winter will be here before we know it! Our official annual winter outlook will be out in October. 

Permanent link to this article: https://indywx.com/new-sst-ca-model-weighs-in-on-winter/

Sep 03

Warmth Next Week Gives Way To A Cool Mid Month…

The refreshingly cool couple days we’ve recently enjoyed will begin to give way to moderating temperatures today.  Humidity levels will remain pleasant and it’ll be a great Labor Day weekend to spend time outdoors.  Highs will top out around 80 today and into the middle 80s Sunday.  Labor Day will feature the mercury climbing closer to the 90 degree mark.  – Fitting, I suppose, for the unofficial end to summer.

Humidity levels will be on the uptick come Monday evening and Tuesday as Gulf moisture is transported northward.

GulfMoistureIt’ll be a downright hot week, as well.  Temperatures will top out around 90 through the end of the short work week.

gfs-ens_T2maMean_us_4As we rumble into next weekend and the following week indications continue to point towards wetter and cooler times.

After a dry week ahead, rain and storms will come with that increased humidity next weekend.

gfs-ens_apcpna_us_7Early numbers off the press suggest 1″-2″ rains possible next weekend.

The increased rain and storm chances signal another shift in the pattern towards a cooler one just beyond the Day 10 period.  From experience, I would look for this trough around mid month to trend deeper (more significant) as time draws closer.

gfs-ens_z500a_us_47It’s possible the first push of widespread 40s loom around the middle of the month.  Time will tell…

Permanent link to this article: https://indywx.com/warmth-next-week-gives-way-to-a-cool-mid-month/