Flash Flood in New Mexico, July 22, 2021

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
1150 AM MDT Thu Jul 22 2021

.AVIATION...
18Z TAF CYCLE
Showers and thunderstorms are expected to develop across the high
terrain by 19Z, before expanding in coverage through the afternoon
and evening as they shift southwestward. The strongest storms will
be capable of heavy rain, MVFR cigs/vsbys and/or mountain
obscurations. One or more clusters of storms may form across western
NM this evening before shifting into AZ. KGUP is likely to be
impacted, perhaps for several hours. Thunderstorms are also possible
at other central and western NM TAF sites, while eastern areas remain
VFR today. Additional showers and thunderstorms may develop across
southeast NM, in the vicinity of KROW, toward sunrise Friday.

34

&&

.PREV DISCUSSION...320 AM MDT Thu Jul 22 2021...
.SYNOPSIS...
A slow moving low pressure system will help trigger scattered to
numerous showers and thunderstorms today. Very heavy rain with the
potential for flash flooding will be most likely in central and
western New Mexico today. Very similar conditions are forecast for
Friday and Saturday with slight drying expected Sunday into early
next week.

&&

.DISCUSSION...
.SHORT TERM...(TODAY THROUGH FRIDAY)...
A Four Corners high will continue today as an upper low embedded in
easterly flow aloft advances west across TX. Although some drying of
the mid levels of the atmosphere was noted in area soundings
yesterday and in the water vapor satellite imagery, PWATs are
forecast by all of the 00Z model solutions to trend back up to above
normal today. The KABQ PWAT is forecast to trend back up from near
0.90" to around 1.2", which will be more than sufficient for locally
heavy rainfall given sufficient destabilization of the atmosphere
from daytime heating. Steering flow will be very light closer to the
upper high center near the Four Corners, but will otherwise be on
the uptrend as winds in the mid levels of the atmosphere increase
out of the northeast given the approaching upper low. The
ingredients for flash flooding will be in place later today, but the
greatest threat will be along/near the Continental Divide given
steering flow that will likely be parallel to the orientation of the
terrain and the potential for training storms. Friday will be
similar, except the upper low will be moving into southeast NM and
steering flow will be on the uptrend. A Flash Flood Watch will need
to be considered for Friday as well given above normal PWATS,
potentially saturated grounds and plenty of instability for deeper
convection. Daytime temperatures will generally be at or below
normal.

LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)...
Global models agree that the above mentioned retrograding upper-
level closed low will be smack dab over NM Friday night. GFS is a
bit farther north than the ECWMF. Somewhat surprisingly, it remains a
cold core feature with -8.5C at 500mb. At any rate, it continues to
increase instability and atmospheric lift over much of central and
especially western NM Saturday. Flash flooding threat remains high
where storms train over the same area but storm steering flow is
forecast to be around 20 kts. The closed low shifts over southwest
AZ/southern CA Sunday but with plenty of low-level moisture in place
in the form of precipitable water values ranging from an inch to
1.25", another round of wet scattered showers and storms will develop
over the mountains and move northward (finally) around 20kts. This
change in steering flow will allow areas missed out so far this year
to get into the action. Models have the same idea for early next
week with the Four Corners' High (FCH) strengthening over CO/WY/NE/KS
and an east-southeast flow aloft over NM. Surface flow remains sely,
keeping moisture advection going with afternoon/evening convection
favoring areas along and west of the central mountain chain. In fact,
both the GFS and ECWMF keep the FCH over KS for the remainder of
next week, keeping daily rounds of convection in the forecast through
next week.

11/33

&&

.FIRE WEATHER...
Daily rounds of wetting storms will persist for the foreseeable
future with the potential for locally heavy rainfall and flash
flooding on/near more recent burn scars. Chances for wetting rain
will favor central and western NM through the weekend and into early
next week. The upper high is forecast to increase in strength and
expand over the region going into the middle of next week, which
should bring warmer temperatures and a smaller wetting rain
footprint.

11

&&

.ABQ WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through late tonight for the following zones...
NMZ202>208-210-211-213>221-241.

&&

Hazardous Weather Outlook
National Weather Service Albuquerque NM
311 AM MDT Thu Jul 22 2021

NMZ201>241-231030-
Northwest Plateau-Chuska Mountains-Far Northwest Highlands-
Northwest Highlands-West Central Plateau-West Central Mountains-
West Central Highlands-Southwest Mountains-
San Francisco River Valley-Tusas Mountains Including Chama-
Jemez Mountains-Glorieta Mesa Including Glorieta Pass-
Northern Sangre de Cristo Mountains-
Southern Sangre de Cristo Mountains-
East Slopes Sangre de Cristo Mountains-Upper Rio Grande Valley-
Espanola Valley-Santa Fe Metro Area-
Middle Rio Grande Valley/Albuquerque Metro Area-
Lower Rio Grande Valley-Sandia/Manzano Mountains Including Edgewood-
Estancia Valley-Central Highlands-South Central Highlands-
Upper Tularosa Valley-South Central Mountains-
Johnson and Bartlett Mesas Including Raton Pass-
Far Northeast Highlands-Northeast Highlands-Union County-
Harding County-Eastern San Miguel County-Guadalupe County-
Quay County-Curry County-Roosevelt County-De Baca County-
Chaves County Plains-Eastern Lincoln County-Southwest Chaves County-
San Agustin Plains and Adjacent Lowlands-
311 AM MDT Thu Jul 22 2021

This hazardous weather outlook is for portions of north and central
New Mexico.

.DAY ONE...Today and Tonight

Scattered to numerous showers and thunderstorms will develop over
central and western NM today, producing heavy rainfall and localized
areas of flash flooding. A flash flood watch remains in effect for
much of central and western areas of the state this afternoon
through late tonight.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Scattered to numerous thunderstorms are expected each afternoon and
evening. Localized areas of flash flooding are likely, with the
greatest risk below recent burn scars and areas where soils are
saturated. Up to 2 inches of rain is possible, especially along and
west of the central mountain chain Friday. Storms will likely
produce small hail and wind gusts to 50 mph.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report rainfall amounts and any flooding
through the National Weather Service Albuquerque web site at
weather.gov/abq or by calling 1.888.386.7637.

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Special Weather Statement
National Weather Service Albuquerque NM
108 PM MDT Thu Jul 22 2021

NMZ206-207-221945-
West Central Highlands-West Central Mountains-
108 PM MDT Thu Jul 22 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL CIBOLA COUNTY UNTIL 145
PM MDT...

At 107 PM MDT, Doppler radar was tracking a strong thunderstorm 15
miles southwest of Grants. This storm was nearly stationary.

Penny size hail and torrential rainfall will be possible with this
storm.

This storm will remain over mainly rural areas of central Cibola
County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3501 10787 3479 10797 3488 10824 3521 10813
TIME...MOT...LOC 1907Z 117DEG 2KT 3497 10800