Pre Loaded Pacific Moisture
Tuesday, September 29, 2026 · 7:48 PM

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Well above normal temperatures through Friday with highs reaching the eighties to lower nineties. Low to medium shower chances develop Friday. Medium to high rain chances Saturday into early Sunday. High chance for more than one inch of rain this weekend with the heaviest rain expected Saturday afternoon into early Sunday morning. Ten to fifteen degrees above normal! The ridge builds high! Humidity rises! Creeping up! Warmer than yesterday! High pressure shifts east! Upper ridge locks overhead! Heat risk moderate! Daytime outdoor heat! Hottest driest September on record! One day to go! Three systems converge! Pocket of Gulf air marching north! Northern stream shortwave dropping fast! Front loading from the west! BOUNDARIES COLLIDE! FRONT MARCHES IN! PRE LOADED PACIFIC MOISTURE! PRE LOADED PACIFIC MOISTURE! Friday approaches! Thirty-six days without rain on the line! Precipitable water over two inches! Ninety-fifth percentile loaded! One half to one point five inches falling fast! Main heavy band stalls out! FAST MOVING FRONT! OVERRUNNING PATTERN! POST-FRONTAL LOW CLOUDS! DRIP INTO MONDAY! BOUNDARIES COLLIDE! FRONT MARCHES IN! PRE LOADED PACIFIC MOISTURE! PRE LOADED PACIFIC MOISTURE! Scooting on through! Clear days ahead! Fifties at night! Seventies by day! PATTERN RESET!
The forecast discussion
KEY MESSAGES
Updated at 745 PM CDT Tue Sep 29 2026
- Well above normal temperatures through Friday with highs reaching the 80s to lower 90s.
- Low to medium shower chances develop Friday.
Medium to high rain chances Saturday into early Sunday.
- High chance for more than 1 inch of rain this weekend with the heaviest rain expected Saturday afternoon into early Sunday morning.
SHORT TERM
(Rest of today through Thursday) Issued at 1145 AM CDT Tue Sep 29 2026
Temperatures are already creeping up, running a few degrees warmer than yesterday at this time.
The warming will continue the next couple of days as surface high pressure shifts to our east and an upper ridge builds overhead.
Along with the building heat, southerly low level flow will bring increasing humidity levels.
Although not record-setting, temperatures will be 10 to 15 degrees above normal Wednesday and Thursday.
Heat risk will climb into the moderate category, so keep that in mind for your daytime outdoor activities.
We have just one more day to go before officially wrapping up the hottest and driest September on record.
The start of October will bring some quick changes in the weather, but the unsettled conditions will last just through the weekend before we settle back into a very pleasant pattern for next week.
LONG TERM
(Thursday night through next Tuesday) Issued at 1145 AM CDT Tue Sep 29 2026
We continue to look for several features to come together late this week to bring much needed rain into our area.
The first will be a disturbance with a pocket of tropical moisture coming up from the Gulf.
The next will be a northern stream shortwave and surface cold front.
Finally, a big southern stream low pressure system will come from the west.
This system will be pre-loaded with Pacific tropical moisture.
The interplay of these systems will make for a complex setup determining exactly when and how much rain we get.
Low to medium rain chances will enter the forecast Friday.
This will take the form of scattered showers and perhaps a few thunderstorms.
If Nashville (BNA) goes the entire day Friday without measurable rainfall, that will officially break the record for the most consecutive days without rainfall; 36 days is the current record.
By Saturday, rain chances will increase area-wide as the various features converge on our area, including arrival of the front from the northwest.
Precipitable water values will reach over 2 inches, or 95th percentile climatologically, so a soaking rain event is likely.
Models have backed off on the number of ensemble members showing several inches of rain.
Most likely we are looking at one half to 1.5" totals, but some areas could get heavier amounts depending on the development of any persistent bands of showers.
The location and persistence of a main, heavier band of rain will depend a lot on the progress of the surface front.
Latest models are trending faster with the front, so it looks like our southeast half has the best chance for higher totals.
Also with the front trending faster, the most significant, widespread rainfall may get swept off to our southeast by mid morning Sunday.
Northwest areas could break out into partial sunshine for Sunday afternoon if the front scoots on through the area.
But with an overrunning pattern, we may deal with post- frontal low clouds and drip for a while, perhaps lasting into early Monday.
After the front completes passage through the area, we will be set up for a very nice pattern next week with dry air and comfortable temperatures.
This means a few clear days with lows mainly in the 50s and highs in the 70s.