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AGUS74 KWCO 201523

HMDNWC



National Hydrologic Discussion - EXPERIMENTAL

NWS National Water Center - Tuscaloosa AL

1015 AM CDT WED MAR 20 2024



.Synopsis...

Isolated flooding impacts possible in East Texas...Potential urban flooding  

in South Florida...Flash, urban, and small stream flooding impacts this  

weekend for Coastal Mid-Atlantic and Northeast...Ongoing river flooding  

with potential renewed rises this weekend in the Southeast..



.Discussion...



.East Texas...

Localized flooding impacts, along with minor riverine flooding, will be  

possible due to locally heavy rainfall through day 2 (Thu) along portions  

of coastal Texas. Antecedent conditions indicate that both streamflows  

(USGS) and surface soils (NASA SPoRT) remain near normal suggesting that  

widespread small stream flooding impacts should be mitigated. Additionally,  

the primary riverine concern may be a few isolated new rises or stalled  

recessions. Some uncertainty remains in the exact location and magnitude of  

the rainfall however, confidence is increasing that portions of the area  

will receive enough rainfall that would produce isolated hydrologic impacts.



.South Florida...

Isolated urban flooding is possible day 3 (Fri) due to potentially heaving  

rainfall of 2 - 4" (WPC QPF) particularly over the southern FL I-75 and  

I-95 corridors. Dry soil conditions (NASA SPoRT) and ample storage in area  

streams and rivers will help to mitigate a majority of potential flash and  

small stream flooding impacts which serve to contain the flood threat  

primarily to poorly drained urban areas.



.Coastal Mid-Atlantic and Northeast...

Isolated flash, urban, and small stream flooding impacts may be possible  

beginning day 4 (Sat) through day 5 (Sun) for portions of the coastal  

Mid-Atlantic region into the Northeast.  A frontal boundary positioned  

across the eastern seaboard may produce training convection with moderate  

rainfall producing totals of up to 3", locally higher, (WPC QPF),  

particularly over DE and NJ.  The National Water Model Medium Range  

Forecast is signaling scattered rapid-onset flooding probabilities and  

isolated AEPs near 10% in the lower order stream reaches. However, riverine  

responses may be somewhat muted as they have receded below flood stage from  

recent rainfall and the heaviest QPF is positioned offshore. Hydrologic  

impacts will likely be isolated in nature and limited to small scale flash  

and urban flooding, especially where training thunderstorms develop.



.Southeast...

Minor river flooding will continue to recede unimpeded for the next couple  

of days as dry conditions continue across the region. The Altamaha River  

(GA) is the last river in moderate stage and the crest will be nearing the  

mouth of the river by day 2 (Thu). Multiple rounds of rainfall beginning  

this weekend may bring renewed rises or delayed recessions across the  

region. However, confidence in the location and magnitude of any flooding  

impacts remains low due to the extended nature of the event.



//Capp



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