Area Forecast Discussion
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172
FXUS64 KEPZ 211850
AFDEPZ

Area Forecast Discussion
National Weather Service El Paso TX/Santa Teresa NM
1250 PM MDT Mon Sep 21 2026

...New DISCUSSION, AVIATION, FIRE WEATHER...

.KEY MESSAGES... Updated at 1249 PM MDT Sun Sep 20 2026

 - Quiet and warm weather will continue today, with just a very
   slight chance of a thunderstorm this afternoon.

 - A cool front will interact with a late season monsoon moisture surge
   and bring widespread showers and thunderstorms to the area
   Tuesday afternoon through Wednesday afternoon. Localized flash
   flooding will be a risk over a large portion of the area.

 - Periods of heavy rain and a risk of flash flooding will
   continue Wednesday and Thursday, before easing up some Friday
   into the weekend.

&&

.DISCUSSION...
Issued at 1249 PM MDT Mon Sep 21 2026

Current WV imagery shows mid-latitude low moving in over SoCal with
narrow band of moisture streaming into it over Arizona.
Further south, plentiful sub-tropical moisture is present, both due
to old cut off low just southwest of the southern Baja, and from
newly formed TS Polo. At the surface, a weak back door cool front
has moved into NE New Mexico.

For today/tonight...should remain relatively quiet. Plenty of CU
development next 3 hours. HRRR showing a few random showers or
thunderstorms possible this afternoon. By late tonight, toward
midnight, the back door front reaches the eastern CWA and into the
central CWA after midnight. HRRR showing isolated shower/storm
activity RG Valley late night.

Tuesday through Thursday...Pacific upper low/trough has now moved in
over the Great Basin and rapidly draws in the sub-tropical moisture
with the help of a developing rather strong sub-tropical jet and a
possible short wave/vort max moving up from northern Mexico. PWs by
Tuesday night approach 1.5 or 1.6 inches in the central and eastern
CWA, which is near record highs for this time of the year. Expect
scattered showers and thunderstorms early Tuesday afternoon and just
continuing through the night into Wednesday morning. A Flood Watch
is in effect for much of the CWA Tuesday into Wednesday. The far
southwest is not included at this time but I may put in with the
next issuance. Wednesday/Wednesday night is still a bit uncertain as
a lot depends on how much cloud cover persists Wednesday morning.
But still expect numerous showers/thunderstorms. Widespread
showers/thunderstorms to continue Thursday into early Friday
morning.

Friday through Sunday...sub-tropical high well established over
southern Texas and begins ridging west across northern Mexico.
This will tend to reduce the moist southerly flow. PWs drop
significantly, ranging from around .6 inches north to 1.1 inch far
southeast. Thus expect showers/storms to become more isolated, with
the risk of flooding lowered significantly (antecedent moisture
issues could continue some flood risk). Cut off low from the
original Pacific trough then moves across the area Friday night.
Lower PWs and dewpoints suggest limited activity Saturday, though
PWs begin rebounding again Sunday. Also moderate moisture gradient
with higher values in northern Mexico could increase activity if it
moves further north than planned. One significant change in the
models; neither GFS/ECMWF are now bringing any tropical storm
remains to our area through the 10 day forecast period.

&&

.AVIATION...
(18Z TAFS) Issued at 1249 PM MDT Mon Sep 21 2026

VFR conditions through the period expected with SCT100 SCT250.
Slight chance of a BKN070CB -TSRA through late afternoon. After
midnight, a few showers/thunderstorms possible around the Rio
Grande Valley. Variable winds AOB 8 knots this afternoon and
evening. Winds briefly east 10-13 knots late tonight east of the
RG Valley.

&&

.FIRE WEATHER...
Issued at 1249 PM MDT Mon Sep 21 2026

Little in the way of fire concerns for this week. Rapidly
increasing moisture Tuesday with lead to widespread showers and
thunderstorms, lasting through Thursday night. Areas of flash
flooding are likely during this period. Showers and thunderstorms
become a bit more isolated Friday through the weekend as moisture
decreases some. Temperatures will be at or below normal all week.

Min RH: Lowlands 25-35% Tuesday increasing to 45-60% Wednesday
through Saturday. Mountains 35-50% Tuesday, increasing to 60-80%
through Thursday, then back to 45-60% Friday and Saturday. Vent
rates fair-good Tuesday, becoming poor-fair Wednesday through
Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
El Paso                  71  89  65  77 /  10  30  80  80
Sierra Blanca            65  86  61  78 /  10  30  80  80
Las Cruces               66  84  61  73 /  10  40  90  90
Alamogordo               65  86  61  75 /  10  40  90  90
Cloudcroft               49  62  47  55 /  10  60  90  90
Truth or Consequences    63  80  60  70 /   0  60 100 100
Silver City              61  77  57  70 /   0  70 100  90
Deming                   66  85  61  75 /   0  50 100  80
Lordsburg                67  82  63  76 /   0  70  80  70
West El Paso Metro       71  88  65  77 /  10  30  80  80
Dell City                66  88  64  80 /  10  30  70  80
Fort Hancock             71  94  67  85 /  10  30  80  80
Loma Linda               64  82  60  72 /  10  30  80  80
Fabens                   70  91  66  81 /  10  30  90  90
Santa Teresa             68  87  63  75 /  10  40  80  80
White Sands HQ           70  86  64  75 /  10  30  90 100
Jornada Range            66  85  62  73 /  10  40  90  90
Hatch                    66  86  62  75 /   0  50 100 100
Columbus                 69  87  64  78 /   0  50  80  70
Orogrande                66  85  62  74 /  10  30  90 100
Mayhill                  54  74  53  66 /  20  70  90  90
Mescalero                53  73  52  66 /  10  60  90  90
Timberon                 53  73  50  64 /  10  50  90  90
Winston                  57  73  54  64 /  10  70 100 100
Hillsboro                65  80  59  71 /  10  60 100 100
Spaceport                64  82  60  71 /   0  50  90  90
Lake Roberts             48  75  54  68 /   0  70 100 100
Hurley                   62  79  58  71 /  10  60 100  90
Cliff                    50  83  58  76 /   0  70  90  90
Mule Creek               47  79  55  73 /   0  50  90  80
Faywood                  64  79  59  70 /  10  50 100 100
Animas                   67  83  63  78 /  10  70  80  60
Hachita                  66  83  62  76 /  10  60  70  60
Antelope Wells           66  84  61  79 /  10  50  60  60
Cloverdale               63  79  59  77 /  10  60  70  70

&&

.EPZ WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch from Tuesday afternoon through Wednesday evening for
     Eastern/Central El Paso County-Northern Hudspeth
     Highlands/Hueco Mountains-Rio Grande Valley of Eastern El
     Paso/Western Hudspeth Counties-Western El Paso County.

NM...Flood Watch from Tuesday afternoon through Wednesday evening 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.

&&

$$

FORECASTER...17-Hefner