Tornado and Flash Flood in New Mexico, August 9, 2018

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
1201 PM MDT Thu Aug 9 2018

.AVIATION...
18Z TAF CYCLE
Modest, but sufficient, increases in moisture will lead to scattered
to numerous showers and thunderstorms today and tonight over New
Mexico. High resolution forecast models indicate storms will initiate
off of the higher terrain, especially in the northern mountains of
the state, before drifting very slowly to the south. Storms are
expected to expand over the remainder of the central mountain chain,
parts of the Rio Grande valley, and eastern plains through the late
afternoon and evening hours. Scattered storms will also develop near
the Continental Divide, but will likely be a bit fewer in number
outside of the Gila/southwestern mountains. Storms will be capable of
producing locally heavy downpours with temporary reductions in
visibility/ceiling. Gusty downburst winds and small hail will also
accompany stronger storms. Storms will likely carry on into the early
morning hours Friday, especially in the east to southeastern plains.

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&&

.PREV DISCUSSION...256 AM MDT Thu Aug 9 2018...
.SYNOPSIS...
A very active day is on tap across the Land of Enchantment.
Widespread showers and thunderstorms are expected this afternoon
through the overnight hours. Slow storm motion combined with plenty
of instability and moisture will result in areas of heavy rain which
may lead to flash flooding. A few severe storms are possible as
well. Another round of widespread storms is expected on Friday,
though abundant cloud cover and cooler temperatures will limit the
instability and mitigate the flash flood threat for many areas.
Drier air is expected over the weekend which will reduce storm
coverage. Temperatures will warm back up early next week, while daily
rounds of storms occur over the mountains.

&&

.DISCUSSION...
A strong outflow boundary has pushed through the gaps of the central
mountain chain and continues to usher low level moisture westward.
This will set the stage for many more thunderstorms than yesterday
near and east of the Continental Divide. Additionally, moist upslope
flow on the Central Mountain Chain will help initiate storms there.
Storm motion will be toward the south and southeast today, but slow,
only around 5 to 10 mph. Plenty of instability will exist this
afternoon, especially just east of the Central Mountain Chain where
lifted indices around -4 to -6 are expected. With PWATs near or just
over 1 inch, combined with the instability and slow steering flow,
decided to issue a Flash Flood Watch for a portion of the area.
The severe weather threat lessens today, though a few severe storms
remain possible. Best chances for severe weather look to be near the
central highlands where the instability and shear values line up the
best, but a pulse severe storm is possible elsewhere. Storms will
last well into the evening and overnight hours across the plains
before diminish toward sunrise.

Another round of storms is expected on Friday, though it looks like
a tongue of mid level dry air will eek into northeast or east central
NM. Models suggest it won't be quite as active on Friday as they were
suggesting yesterday, but still plenty of storms to contend with.
With that said, due to the cloud debris throughout the morning, it
will be much cooler on Friday, and will not be quite as unstable when
storms develop in the afternoon. Severe weather will be unlikely,
PWATs actually decrease a little, and storm motion will be toward the
southwest around 10 to 20 mph. These factors should mitigate the
flash flooding threat somewhat. Portions of the southeast plains is
the area of most concern attm, near a weak upper low/trough/MCV,
where storm motion is weakest.

The weekend looks to trend drier across all but the southeast quarter
of the area. This area will be in the vicinity of the aforementioned
weak upper low that meanders around. Elsewhere, drier air will filter
in from the north and northeast reducing storm coverage.

The upper high will slowly build back into the desert southwest early
to mid week. Temperatures will trend back upward, and daily round of
isolated to scattered storms over the mountains should be the rule.

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&&

.FIRE WEATHER...
An active weather pattern to continue through the foreseeable future.
High pressure will settle over NV and UT today and Friday then shift
east this weekend. An upper level trough will form this weekend near
the NM and TX border before lifting northeast early next week. High
pressure will then build over the Four Corners area later next week.

Yesterday's crop of thunderstorms delivered low level moisture into
the Rio Grande Valley west to the AZ border overnight. This will set
the stage for an active day today with widespread showers and storms
developing this afternoon and evening and continuing well into the
night. Flash flooding will be a significant concern, especially on
recent fire burn scars. Highs will be a few degrees lower today
while humidities will be 5 to 15 percent higher except in the
northeast.

A similar day on Friday with widespread wetting rain from showers
and thunderstorms. Again flooding will be a concern. Highs will
continue to trend lower and humidities higher.

Despite an upper low nearby, the weekend will trend drier as
northerly flow around the upper low brings in some drier air at mid
and upper levels. The upper low will transition northeast early next
week as high pressure tries to build in from the west. The high may
reach the four corners area Wednesday and Thursday but will retreat
to the northwest after that. Next week will be active isolated to
scattered showers and thunderstorms each afternoon and evening,
favoring the mountains.

CHJ

&&

.ABQ WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through late tonight for the following zones...
NMZ508-512>515-521>523-528-529-532-533-537.

&&

Hazardous Weather Outlook
National Weather Service Albuquerque NM
310 AM MDT Thu Aug 9 2018

NMZ501>540-101100-
Northwest Plateau-Chuska Mountains-Far Northwest Highlands-
Northwest Highlands-West Central Plateau-West Central Mountains-
West Central Highlands-Southwest Mountains-
San Francisco River Valley-San Juan Mountains-Jemez Mountains-
West Slopes Sangre de Cristo Mountains-
Northern Sangre de Cristos above 9500 feet/Red River-
Southern Sangre de Cristos above 9500 feet-
East Slopes Sangre de Cristo Mountains-Upper Rio Grande Valley-
Lower Chama River Valley-Santa Fe Metro Area-
Middle Rio Grande Valley/Albuquerque Metro Area-
Lower Rio Grande Valley-Sandia/Manzano Mountains-Estancia Valley-
Central Highlands-South Central Highlands-Upper Tularosa Valley-
South Central Mountains-Raton Ridge/Johnson Mesa-
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-
310 AM MDT Thu Aug 9 2018

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

.DAY ONE...Today and Tonight

Widespread showers and thunderstorms are expected across New Mexico
this afternoon through the overnight hours. Storm motion will be slow
and enough instability will exist for heavy rainfall. Flash flooding
will be possible, especially on areas that have received recent heavy
rains, as well as burn scars. A few severe storms are also possible
today, favoring areas in the vicinity of the central highlands.
Large hail and damaging winds are the main threats.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Widespread showers and thunderstorms will continue on Friday. Locally
heavy rain and flash flooding is possible, especially where soils are
saturated.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report rainfall amounts, flooding, hail
and strong wind gusts through the National Weather Service
Albuquerque web site at weather.gov/abq or by calling 1.888.386.7637.
You can also submit storm reports and photos on our Facebook page or
via Twitter using the hashtag nmwx.

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