Flash Flood Guidance
Issued by NWS
Issued by NWS
324 AWUS01 KWNH 212359 FFGMPD TXZ000-OKZ000-NMZ000-220555- Mesoscale Precipitation Discussion 1039 NWS Weather Prediction Center College Park MD 758 PM EDT Sat Sep 21 2024 Areas affected...TX Panhandle into adjacent eastern NM/western OK Concerning...Heavy rainfall...Flash flooding possible Valid 212357Z - 220555Z SUMMARY... Repeating and training of cells are expected to pose a threat for flash flooding from the TX Panhandle into adjacent eastern NM/western OK through 06Z. Rainfall rates of 1-2 in/hr and totals of 2-4 inches are expected. DISCUSSION...2330Z radar imagery showed a small cluster of thunderstorms advancing through the western TX Panhandle, with more widely scattered coverage extending westward into eastern NM. These cells were forming out ahead of a potent mid-level trough over the Four Corners region, which was advancing toward the ENE, with favorable shear for organized cells in place over the High Plains. While most cells were moving toward the NE at 25-35 kt, some deviant rightward motion of organized cells has been observed and instances of training have supported MRMS-derived rainfall rates of about 1-2 in/hr. Surface observations showed an effective cold front (outflow boundary enhancement) extended southwestward through northwestern OK into the TX Panhandle, and then west-northwestward into NM. A pool of 1000 to 2000+ J/kg MLCAPE was estimated via the 23Z SPC mesoanalysis from just south of AMA into eastern NM along with anomalous precipitable water values that ranged from 1.3 to 1.7 inches. A strengthening low level jet is forecast with 25 to 35+ kt through 06Z at 850 mb, which will act to overrun the southward sinking effective cold front. Moisture pooling and elevated instability of up to 1500 J/kg is forecast by the RAP to focus over the TX Panhandle north of the boundary, with weaker values of up to 500 into western OK. After the initial round of thunderstorms advances east from the western TX Panhandle, subsequent rounds are anticipated as the low level jet ramps up overnight, leading to instances of repeating and training due to the similar boundary orientation and anticipated storm motions. Rainfall rates should generally fall in the 1-2 in/hr range and total rainfall of 2-4 inches through 06Z may lead to some areas of flash flooding, though dry antecedent conditions may limit flash flooding to urban areas or otherwise flashy locations across the region. Otto ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...ABQ...AMA...LUB...OUN... ATTN...RFC...ABRFC...WGRFC...NWC... LAT...LON 36240090 36210007 35829981 35149991 34370074 33860247 33950309 34330322 34830311 35300282 35870192