Area Forecast Discussion
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253
FXUS64 KEPZ 281746
AFDEPZ

Area Forecast Discussion
National Weather Service El Paso TX/Santa Teresa NM
1146 AM MDT Mon Sep 28 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1142 AM MDT Mon Sep 28 2026

 - Moisture from tropical remnants of Polo will bring more
   widespread showers and thunderstorms to the Borderland through
   Tuesday night. Storms will be capable of heavy rain, gusty
   winds, and flash flooding, especially over locations that have
   already received heavy rain in recent weeks.

 - New rain amounts around 2 inches across much of southern New
   Mexico, with localized areas receiving 3 to 4 inches. A Flood
   Watch is in effect into Wednesday morning.

 - Drier weather expected Thursday through the weekend as the
   moisture is pushed eastward. Temperatures remaining cool into
   next weekend.

&&

.DISCUSSION...
Issued at 1100 PM MDT Sun Sep 27 2026

...FLOOD WATCH IN EFFECT FROM MONDAY AFTERNOON THROUGH WEDNESDAY
MORNING...

Two weather features to focus on in the short term are the upper
low currently centered over northern California and Hurricane Polo
spinning off the Baja California coast. Tropical steering pattern
is favorable for Polo to drift north on Monday, making likely
landfall over Baja California Sur during the evening hours. At the
same time, the mid-latitude Pacific low aloft will make a
southeast dive down to the Colorado River Valley, forced by a
strengthening 75-knot jet streak on its backside. A weakening Polo
will latch onto this stronger mid-latitude flow, shifting it
northeast into Sonora/Chihuahua and straight toward El Paso on
Tuesday.

Monday will feature a rapid moisture increase locally, thanks to
the approaching tropical remnants. Veering of mid-level winds to
the south ahead of the Pacific low will pull in deep, tropically-
sourced moisture into southern New Mexico and far west Texas.
Precipitable water values, measured at just 1.1" this evening
(00Z KEPZ RAOB), will spike to 1.5-1.6" Monday evening. This may
break seasonal moisture records for El Paso, and is easily 3 to 4
standard deviations higher than usual for the end of the monsoon
season. This moisture-rich atmosphere, combined with PVA and
increasing diffluent flow aloft, will lead to widespread showers
and thunderstorms area wide starting as early as Monday afternoon.

Good confidence in rain for all local zones Monday night through
Wednesday morning as the upper low pulls up tropical moisture like
a fire hose into New Mexico and West Texas. 48-hour rainfall
forecasts suggest widespread totals ranging from 1.00-2.00". NBM
guidance backs this up. Stronger storms and training (or multiple
rounds) of rain showers over the same areas will lead to localized
3-4". Soil saturation is very high right now, so rain will lead
to rapid runoff and flash flooding quickly. A Moderate (Level 3 of
4) Risk of flash flooding is in place almost area-wide for
Tuesday. Of particular concern for me will be the Sacramento
Mountains, which have already had an above-normal precipitation
season and significant flooding over the past two weeks. A Flood
Watch is in effect area-wide from Monday afternoon through
Wednesday morning. WFO El Paso will be proactive with flood
warnings in areas with recent heavy rains if needed Tuesday-
Wednesday.

On top of the heavy rain risk, the passing tropical depression
may still have some stronger winds associated with it. 00Z HRRR
run tonight was of particular concern, and recent NAM runs have
also picked up on the potential for gusty conditions Tuesday
evening as Polo moves through. Increased forecasted winds for
Tuesday afternoon/evening, especially for El Paso, Hudspeth, Otero
counties where strong winds out of the south just ahead of the
anticipated storm track could lead to gusts in the 30-40 mph
range.

Both GFS and ECMWF global models show a track of the upper low
progressing across central NM on Wednesday. Rain showers will
slowly decrease in coverage Wednesday morning, with the remnants
of Polo quickly dissipating. Subsident "dry-slotting" at the base
of the low will lead to drier weather for our area by Wednesday
afternoon.

Once all this action passes, it looks like a fairly "boring"
weather pattern for the start of October. Strengthening upper high
over the U.S. Southwest will usher in a much-needed break from
rainfall. Continued east surface flow could keep temperatures
below normal through the rest of the week. Lowland highs lingering
in the upper 70s into next weekend seems like the best bet right
now.

&&

.AVIATION...
(18Z TAFS)
Issued at 1142 AM MDT Mon Sep 28 2026

Showers with embedded thunderstorms are ongoing late this morning
but this is the beginning of the heavy rain event we`re expecting.
Storm coverage will expand all across the area after 00Z tonight
with persistent light to moderate rainfall throughout the day
tomorrow. Expect some breezy winds at KTCS this afternoon.
Breezier conditions for all sites expected tomorrow morning and
into the afternoon.

&&

.FIRE WEATHER...
Issued at 530 AM MDT Mon Sep 28 2026

No fire weather concerns are forecast through the week. Increasing
moisture and rain chances today, becoming widespread by tonight.
High rain chances continue through Tuesday night with a medium-high
risk of flash flooding, worsened by saturated soils from last
weeks` rainfall. Winds will be breezier today from the south with
near-normal temperatures. Cooler tomorrow with possibly strong
winds in the evening for eastern areas as Polo`s remnants come
across the region. Rain chances quickly decrease Wed AM behind the
passing upper low with mainly dry conditions beginning Thu.
Temperatures remain below normal into next weekend.

Min RHs range from 35-55% today, rising to 60-90% Tue. Vent rates
will be fair to good this afternoon, then mostly poor tomorrow.

&&

.PRELIMINARY POINT TEMPS/POPS...
El Paso                  66  79  60  74 /  80 100  60  10
Sierra Blanca            62  80  59  72 /  90  70  60  20
Las Cruces               63  73  55  70 /  90 100  70  10
Alamogordo               63  75  56  71 /  90 100  60  40
Cloudcroft               49  56  42  50 /  90 100  80  50
Truth or Consequences    62  70  54  70 /  90 100  80  20
Silver City              58  65  49  63 / 100 100  70  50
Deming                   62  74  53  72 /  90  90  70  10
Lordsburg                62  72  53  69 /  90  90  80  20
West El Paso Metro       66  79  60  74 /  90 100  50  10
Dell City                65  82  61  75 /  80  90  60  20
Fort Hancock             68  88  64  81 /  90  80  50  20
Loma Linda               61  74  55  67 /  90  90  60  20
Fabens                   66  84  61  77 /  90  90  60  20
Santa Teresa             64  77  58  72 /  80 100  60  10
White Sands HQ           64  76  58  72 /  80  90  60  10
Jornada Range            63  73  55  71 /  90  90  80  10
Hatch                    64  75  55  73 / 100  90  80  10
Columbus                 64  76  57  74 /  80  80  40  10
Orogrande                63  75  56  70 /  90  80  50  10
Mayhill                  55  67  48  64 /  90 100  80  20
Mescalero                54  66  47  60 / 100 100  80  60
Timberon                 52  63  47  58 / 100 100  60  40
Winston                  55  64  46  64 / 100 100  80  20
Hillsboro                60  71  53  71 / 100 100  80  10
Spaceport                61  71  53  70 /  90  90  80  10
Lake Roberts             54  64  46  62 / 100 100  70  50
Hurley                   58  68  50  66 /  90 100  70  30
Cliff                    61  71  54  69 / 100 100  90  60
Mule Creek               57  66  50  65 /  90  90  90  60
Faywood                  60  68  51  66 /  90 100  70  10
Animas                   63  74  54  72 /  80 100  70  10
Hachita                  61  73  53  71 /  80  90  50  10
Antelope Wells           62  74  54  72 /  80  90  60  10
Cloverdale               59  68  52  67 /  90 100  80  10

&&

.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch through late Tuesday night for Eastern/Central El
     Paso County-Northern Hudspeth Highlands/Hueco Mountains-Rio
     Grande Valley of Eastern El Paso/Western Hudspeth Counties-
     Rio Grande Valley of Eastern Hudspeth County-Salt Basin-
     Southern Hudspeth Highlands-Western El Paso County.

     Wind Advisory from noon Tuesday to 9 AM MDT Wednesday for
     Eastern/Central El Paso County-Northern Hudspeth
     Highlands/Hueco Mountains-Rio Grande Valley of Eastern El
     Paso/Western Hudspeth Counties-Rio Grande Valley of Eastern
     Hudspeth County-Salt Basin-Southern Hudspeth Highlands-
     Western El Paso County.

NM...Flood Watch through late Tuesday night for Central Grant
     County/Silver City Area-East Central Tularosa
     Basin/Alamogordo-East Slopes Sacramento Mountains Below
     7500 Feet-Eastern Black Range Foothills-Lowlands of the
     Bootheel-Northern Dona Ana County-Otero Mesa-Sacramento
     Mountains Above 7500 Feet-Sierra County Lakes-Southeast
     Tularosa Basin-Southern Dona Ana County/Mesilla Valley-
     Southern Gila Foothills/Mimbres Valley-Southern Gila Region
     Highlands/Black Range-Southwest Desert/Lower Gila River
     Valley-Southwest Desert/Mimbres Basin-Uplands of the
     Bootheel-Upper Gila River Valley-West Central Tularosa
     Basin/White Sands-West Slopes Sacramento Mountains Below
     7500 Feet.

     Wind Advisory from noon Tuesday to 9 AM MDT Wednesday for East
     Central Tularosa Basin/Alamogordo-East Slopes Sacramento
     Mountains Below 7500 Feet-Otero Mesa-Sacramento Mountains
     Above 7500 Feet-Southeast Tularosa Basin-Southern Dona Ana
     County/Mesilla Valley-West Central Tularosa Basin/White
     Sands-West Slopes Sacramento Mountains Below 7500 Feet.

&&

$$

FORECASTER...37-Slusher