Frantic About FrancesRichard H. Grumm and John LaCorteNational Weather ServiceState College, PA 16803

IntroductionSignificant Hurricane as approached FloridaHad a big impact on FloridaRaised issues of impacts as it moved northWould the track and timing be better than withCharlie?Big issue was the transition stageHeavy rains, tornadoes, and winds Frances was a large storm lots of anomalies in wind, moisture and pressure fields And timing of heavy rain, tornadoes, and windTiming was in doubt due to model differences in the speed of movement Heavy rains on north and west side of the storm in Pennsylvania, New York, and OhioCold conveyor rains (heavy) in western New York, PA, and OH.

Francesthe hurricanenot the mule

MODUS Image as CAT-3 Storm3 Sept 2004

4 Sept GOES-12

Track through transitionbased on TPC and John LaCortes analyses

Florida and beyondBig impact of Big Storm Floridas East CoastWinds and rainTornadoesExpectations of storm as it moved northwardCharlie had a bad track record (more on this later!)Where would it rain and would there be significant winds etc.Tornadoes were a problem tooMainly in the feeder bands within the warm tropical air mass.Okay, Ivan, terrible as it wasproduced more tornadoes.

Tornadoes on the 6th

54 Tornadoes on the 7th

26 Tornadoes on the 8th

Eta 00-hour 850 hPa wind anomalies0000 UTC 8 September Extremely anomalous southerly winds ahead of the system5-6 Standard Deviation above normal windsStrong shear produced tornadoesThe strong wind anomalies persisted, though weakened as the storm moved northwardNote evolving easterly jet north of the cyclonefocus for heavy rains

850 Winds 9 September 0000 UTCStill had anomalously strong low-level winds in the warm sector east of the surface low centerLast day of tornadoes in Mid-Atlantic regionTornadoes in the feeder bands and in the warm tropical airThe easterly jet was now well-developed north and west of the main lowCold conveyor belt area of heavy rainfallWell north of the cyclone center and removed from the tropical air at low-levels

0000 UTC 9 SeptemberLow up western slopes AppalachiansAnomalous precipitable waterEven in the cool air in western PA and OHStrong LLJ into Mid-AtlanticStrong northeasterly jetCold conveyor

KCCX Storm Total Estimated RainfallHeaviest rains were well to the westWestern PA and Ohio hard hitNot nearly as much rainfall in the warmer air to the eastThe cold conveyor rain effect dominated in this event.

KPBZ estimated Rainfallreal rainfall shown laterMore reliance on tropical Z-RThere was some very heavy rain in eastern OhioSame overall pattern as KCCX though this extends farther west

GFS Forecasts For Frances

Eta Forecasts For FrancesEta taken it slowly?

0000 UTC 09 SeptemberHeavy rains in cold conveyor belt region

Note temperatures in the 60s.L

0000 UTC 09 SeptemberHeavy rains in cold conveyor belt region

Note temperatures in the 60s.Tropical airL

Cold conveyor rainRain shield heavy rain north and west of surface lowStrongly baroclinicNorthern ageostrophic windsStrong low- and mid-level forcing (Frontogensis)Not most common concept heavy rain in tropical systems but big in Mid-Atlantic /northeastern US

Frontogenetic Rains0000 UTC 9 Sept 850 FGEN/OBS/AGE 1000 hPa

ETA 0600 UTC 9 Sep

1200 UTC 9 Sept

RUC FGEN and OBS

0500 UTC RUC

0800 UTCrain/FGEN anchored in cold airmoving north

1200 UTC 9 Septrain about over in PA!L

1800 UTC 9 SeptemberL

Eta Forecasts For FrancesEta got faster with time but initially missed Oswego area locaiton!

The Eta and Tropical Storm TracksThe Eta was too slow with FrancesThe GFS did a better job and was more consistentSREFS were good too.This lead to rainfall forecasts and flood products talking about rainfall into the day of the 9th in PAThe rain ended in most locations before 1200 UTCLets look at the woeful Eta forecasts for Charlie

Eta Tracks with Charlieall valid 12Z 15 August initialized different times

GFS Tracks of Charlie all valid 12Z 15 August initialized different times

Hard to make good rainfall analyses

Central Appalachian Zoomed in viewpower of databases and arcview

Central Pennsylvania

New York

A word about rainfallNot very standardized dataWe need better means/methods to share dataPost analysis is not so easy with such sporadic dataWe could put together most but not all of the pictureWe really need to improve sharingSnowfall and rainfall data for good case reviewsThis needs to be done in near real-time

ConclusionsFrances wreaked some havocIn Florida as a hurricaneIn the southeast-Mid-Atlantic as Rain and tornado machineCentral PA had mainly a cold rainRemained in cool low-level air when the heavy rains arrivedTrack of the stormThe GFS was faster with storm progression and better than the track of the EtaThe Eta has this slow bias with moving tropical storms.what's up with that?Ensembles (not shown) are a better way to go.