Colorado Mesoscale Discussion

Areas affected…Eastern New Mexico, Southeastern Colorado

Concerning…Heavy rainfall…Flash flooding possible

Valid 211945Z – 220145Z

Summary…Slow moving thunderstorms with torrential rainfall will
become more widespread into this evening. Rainfall rates may reach
2″/hr at times. Flash flooding is possible.

Discussion…Broad mid-level ridge of high pressure from Arizona
to Texas is pumping warm moist air into the Southwest. Within this
environment, PWATs have risen to 0.75-1.0″, and as high as 1.06″
in eastern NM according to latest GPS PW observations. Although
these values are near the climatological normal for the area, they
are combining with MUCape analyzed by the 19Z RAP of more than
2000 J/kg to create a thermodynamic environment favorable for
convection with heavy rainfall.

As usual in this favorable environment, widespread agitated CU and
thunderstorms have developed along and within the terrain of the
discussion area. Convection is expected to continue to blossom as
heating and instability persist, and low-level convergence
increases in the vicinity of a slow moving front dropping through
eastern CO, and a weak low-level trough axis analyzed in eastern
NM. High-res CAMS, including the last several runs of the HRRR and
ARW2, suggest thunderstorms will become widespread through the
afternoon before slowly shifting eastward this evening.

It is this storm motion which will create a localized flash flood
threat through the evening. Despite the lack of anomalous moisture
and HREF neighborhood probabilities that are modest for rainfall
rates above 1″/hr, 0-6km mean winds are 0-5 kts which implies
storms may linger temporally over any given area. This could also
lead to boundary interactions/storm mergers with briefly heavier
rain rates as the lack of bulk shear leads to primarily pulse
convection which should produce outflows to spawn renewed
convection. With FFG across the region as low as 1″/1hr, and
1.5″/3hrs, there exists the potential that where these storms
linger, rainfall could exceed FFG leading to flash flooding. This
will be most likely across any urban areas or burn scars, or where
the aforementioned storm mergers briefly produce heavier rain


…Please see for graphic product…



LAT…LON 39390400 38860360 38290338 37420317 35780316
34850343 34310384 34000435 33880488 33860537
34400567 36050581 37530573 39130541 39090539

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.