Radar is filling in as the air column becomes saturated. Precip in the form of snow or rain/snow turning to snow should start within the hour. The snow will be light and primarily non-accumulating for an hour or 2 before temps drop.
 |
| Radar does not update |
The SPC issued a mesoscale discussion highlighting the threat of heavy snow with rates around 1 inch per hour.
MESOSCALE DISCUSSION 0195
NWS STORM PREDICTION CENTER NORMAN OK
0328 PM CDT SUN MAR 16 2014
AREAS AFFECTED...PORTIONS OF CENTRAL/ERN WV INCLUDING THE
PANHANDLE...CENTRAL/NRN VA...MUCH OF MD...DC
CONCERNING...HEAVY SNOW
VALID 162028Z - 170230Z
SUMMARY...SNOW WILL DEVELOP THROUGH EARLY EVENING WITH RATES OF ONE
INCH/HR DEVELOPING BY...AND ESPECIALLY BEYOND...02Z.
DISCUSSION...A LARGE AREA OF PRECIPITATION CONTINUES TO LIFT NEWD IN
ASSOCIATION WITH ISENTROPIC LIFT AHEAD OF A DE-AMPLIFYING UPPER LOW
OVER THE MID-MS VALLEY. A DIFFUSE SFC LOW...CURRENTLY OVER NERN
MS...WILL MOVE INTO THE SRN APPALACHIANS BY 02Z. RESULTING N/NE
LOW-LEVEL FLOW WILL CONTINUE TO ADVECT VERY DRY AIR INTO THE
DISCUSSION AREA...AND INITIALLY DRY LOWER LEVELS OF THE ATMOSPHERE
WILL COOL/SATURATE WITH TIME ALLOWING FOR SNOW TO BECOME THE
DOMINANT P-TYPE...BECOMING WIDESPREAD DURING THE EVENING HOURS.
LATEST GUIDANCE CONTINUES TO DEPICT A STRENGTHENING BAROCLINIC ZONE
ACROSS THE DISCUSSION AREA THIS EVENING WITHIN CONFLUENT 700 MB
FLOW...WITH DEFORMATION-INDUCED FRONTOGENESIS EXPECTED TO DEVELOP
WITHIN THE 800 MB TO 700 MB LAYER. MESOSCALE BANDING WILL LIKELY
PRODUCE SNOWFALL RATES OF ONE INCH/HR BY...AND ESPECIALLY
BEYOND...02Z.
..BUNTING.. 03/16/2014
ATTN...WFO...PHI...AKQ...LWX...RNK...PBZ...RLX...
LAT...LON 39128038 39517834 39517611 38917585 38287607 37887711
37677889 37668001 37788053 38258095 39128038
4:45PM UPDATE:Light rain/snow showers have broken out across the area. This is a little earlier than expected but this should not significantly affect our snow totals. Temps are in the upper 30s to low 40s and dropping fast. The upper levels are cold and therefore conducive for snow. The simple fact that it is snowing with temps in the 40s attests to the shallowness of the warm layer. Recent model runs have held steady with the idea that the DC area is the jackpot. We have an increasing chance that this storm may exceed snowfall expectations. In the middle of March. The WPC has us in the high chance (>70%) of getting at least 4 inches of snow and a moderate chance (>40%) of getting 8 inches.
 |
| Chance of snow accumulation >8 inches |
Go with the NWS forecast, not mine since I have no experience. I just put my guess of 3-5 inches out for the record.
The NWS forecast:
The NWS rationale to raising snow totals:
ADJUSTMENTS FROM THE MORNING FORECAST INCLUDE...BUMPING UP SNOWFALL TOTALS ACROSS THE NORTHERN CWA THINKING MOST AREAS WILL BE SOUTH OF THE GRADIENT THAT SETS UP NEAR THE MASON-DIXON LINE. ALSO...LATEST GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR MESOSCALE BANDING ACROSS THESE AREAS LATE TONIGHT INTO MONDAY MORNING...WHICH COULD CAUSE HIGHER SNOWFALL AMOUNTS. THE WARNING HAS BEEN EXTENDED IN AREA TO INCLUDE ALL OF NORTHERN VIRGINIA...PORTIONS OF THE EASTERN WEST VIRGINIA PANHANDLE AND THE BALTIMORE METROPOLITAN AREA. THE WARNING MAY NEED TO BE EXPANDED EVEN FARTHER NORTH TOWARD THE MASON-DIXON LINE DEPENDING ON EXACTLY WHERE THE HEAVIER BANDS OF SNOW DEVELOP.2:00PM UPDATE:
Temperatures have risen into the mid to upper 40s. However, dewpoints have dropped into the upper teens. Temps should halt their rise and begin to drop as clouds roll in from the west. This is the anxious waiting time. I'm going to say 3-5 inches for the area (up from 2-4 too much for those who saw that) . Do be aware that it could be lower if temps lag. The NWS has gone more aggressive, with 4-8 inches for the southern part of the county and 3-7 for the northern part.
ORIGINAL TEXT:
The National weather service has issued a Winter Storm Warning for Montgomery County and points south.
THE NATIONAL WEATHER SERVICE IN BALTIMORE MD/WASHINGTON HAS ISSUED A WINTER STORM WARNING FOR SNOW...WHICH IS IN EFFECT FROM 7 PM THIS EVENING TO 2 PM EDT MONDAY. THE WINTER STORM WATCH IS NO LONGER IN EFFECT. * PRECIPITATION TYPE...SNOW * ACCUMULATIONS...3 TO 6 INCHES. * TIMING...A MIX OF RAIN AND SNOW EARLY THIS EVENING WILL CHANGE TO ALL SNOW BY MID EVENING. SNOW WILL CONTINUE OVERNIGHT THROUGH EARLY AFTERNOON MONDAY. THE HEAVIEST SNOW IS EXPECTED AFTER MIDNIGHT TONIGHT THROUGH EARLY MONDAY MORNING. * TEMPERATURES...FALLING INTO THE LOWER 30S BY MID EVENING AND THEN DROPPING INTO THE MID TO UPPER 20S LATE TONIGHT. HIGHS MONDAY IN THE LOWER 30S.
As usual, temperatures will be an issue and if we don't drop as fast as modeled, we may just get non accumulating snow. That being said, Models have also bought into a more northerly solution with more precip. Need to go out. Updates late.
No comments:
Post a Comment