FOUS30 KWBC 160802
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
402 AM EDT Wed Oct 16 2024

Day 1
Valid 12Z Wed Oct 16 2024 - 12Z Thu Oct 17 2024

The probability of rainfall exceeding flash flood guidance is less than
5 percent.

Kleebauer


Day 2
Valid 12Z Thu Oct 17 2024 - 12Z Fri Oct 18 2024

...2030Z Update...

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Kleebauer


Day 3
Valid 12Z Fri Oct 18 2024 - 12Z Sat Oct 19 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTHERN NEW MEXICO INTO SOUTHERN COLORADO...

Longwave pattern will evolve into a fairly prolific upper
trough/closed-low over the Great Basin, slowly migrating eastward
with sights on the Four Corners. Large scale ascent will become
maximized downstream of the mean trough with a pronounced diffluent
pattern in-of the Southern Rockies, including the Sangre de Cristo
and San Juan mountain ranges where heavier precip is forecast. A
cold front will slowly propagate eastward from the primary
disturbance with a return flow setup pressing westward across the
Eastern NM plains on the western flank of a sprawling surface high
east of the Mississippi. A secondary cold front to the north will
plunge southward thanks to a strong ridge of high pressure
developing upstream in wake of the primary western low, along with
a lee side trough developing over the Front Range. The tandem of
boundaries and backed flow will converge over Northern NM with a
strong isentropic ascent pattern initiating later Friday evening
through Saturday AM and beyond. 

Convective signals are most pronounced in the initial stages of 
the pattern evolution mainly due to the return flow setup where 
more unstable air will advect northwestward into the Eastern NM 
plains before banking against the lee of the Southern Rockies. Both
ensemble and deterministic output for heavy precip are locked in 
across the area encompassing much of Northern NM, but especially 
within the confines of places like Raton and points south where 
topographic enhancement within the convergent axis will generate 
local precip maxima when the convergence pattern truly solidifies 
late in the period. Totals of 1-2" of precip are forecast on the 
southern edge of the San Juans down into portions of the Sangre de 
Cristos, closing in on some of the prevalent burn scars in the 
region. A secondary maxima of 1-2" is forecast over that main axis 
of convergence over Northeastern NM in vicinity of the eastern 
flank of the Sangre de Cristos, including places like Taos and 
Angel Fire over into parts of the plains in the lee of the mountain
chain. The period before will be more of a primer for the main 
event this period through the following D4 time frame. The 
combination of better moisture return and large scale forcing via 
diffluent mid- level flow and jet coupling provides ample support 
for a continuation of the previous MRGL risk, as well as an 
expansion of the risk area further southwest and east to match the 
ensemble QPF footprint in areas of highest convective potential.

Kleebauer
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