michael l. jurewicz, sr. noaa/nws, binghamton, ny northeast regional operational workshop
DESCRIPTION
2008 “PRE-Season” In Review: A Comparison of Tropical Cyclones Fay, Hanna, and Ike with Regards to Predecessor Rainfall Event (PRE) Development. Michael L. Jurewicz, Sr. NOAA/NWS, Binghamton, NY Northeast Regional Operational Workshop November 5-6, 2008. Fay. Fay Overview. - PowerPoint PPT PresentationTRANSCRIPT
2008 “PRE-Season” In Review: A Comparison of Tropical
Cyclones Fay, Hanna, and Ike with Regards to Predecessor
Rainfall Event (PRE) Development
Michael L. Jurewicz, Sr.NOAA/NWS, Binghamton, NY
Northeast Regional Operational WorkshopNovember 5-6, 2008
Fay
Fay Overview
Fay came ashore as a Tropical Storm over the FL Keys on Aug. 19, then slowly meandered across the FL Peninsula the next several days
Synoptic Back-drop: Cutoff low over the southern plains Large, building anticyclone over the eastern
U.S., to the north and northeast of Fay
700 mb Analysis, 1200 UTC, 19 Aug.
LFay
Ridge Axis
925 mb Analysis, 1200 UTC, 19 Aug.
LFay
Ridge Axis
300 mb Analysis, 1200 UTC, 19 Aug.
SR Null-Case Composites
700 mb heights (dam) and upward vertical motion (shaded, μb s-1)
925 mb heights (dam), θe (K), and 200 mb winds (shaded, m s-1)
Center of composite TC
24-Hour QPE Through 1200 UTC, 20 Aug.
Fay’s Direct Rainfall
Radar Mosaic, 2100 UTC, 20 Aug.
Parcel Trajectories
Red – About 925 mbBlue – About 700 mbGreen – About 500 mb
700 mb Analysis, 1200 UTC, 21 Aug.
LFay
Ridge Axes
24-Hour QPE Through 1200 UTC, 21 Aug.
Fay’s Direct Rainfall
Disorganized Convection
Radar Mosaic, 1800 UTC, 21 Aug.
Parcel Trajectories
Red – About 925 mbBlue – About 700 mbGreen – About 500 mb
700 mb Analysis, 1200 UTC, 22 Aug.
L
Fay
Ridge Axes
24-Hour QPE Through 1200 UTC, 22 Aug.
Still Disorganized Convection
Fay’s Rainfall
Radar Loop – 20 Aug. to 24 Aug.
A Classic Null-Case
Fay produced tremendous rainfall across parts of the Southeastern U.S. Several day totals of 20”+ in parts of FL Due to the direct impacts of Fay’s rainfall shield
and her slow movementPRE development not observed
Expansive mid-level ridge was in place; nearly enveloped Fay
Precipitation maxima stayed tightly clustered around the circulation center
Hanna
Hanna Overview
Hanna came ashore as a Category 1 Hurricane near the NC/SC border around 0600 UTC, 6 Sept.
Synoptic Back-drop: Large western Atlantic ridge and central U.S.
troughiness Deep southerly flow regime over the eastern states
700 mb Heights/Winds, 0000 UTC, 6 Sept.
925 mb Heights/Theta-E and 200 mb Winds, 0000 UTC, 6 Sept.
Theta-E Ridge Line
Hanna Falls Within the SR Category; SR TC Tracks and PRE Locations
All SR TC Tracks All SR PPTC Tracks; with PRE centroids (colored dots)
SR PPTC Composites (PRE - 12)SR PPTC Composites (PRE - 12)
Center of composite TC
Trough axis
Ridge axis
θe-Ridge axis
700 mb heights (dam) and upward vertical
motion (shaded, μb s-1)
925 mb heights (dam), θe (K), and 200 mb winds
(shaded, m s-1)
Mid-level Streamlines
Representative TC Tracks
TC Rainfall
PREs
LL θe-Ridge Axis
See inset
UL Jet
Conceptual Model: LOT PRE Ahead Of SR Or AR TCConceptual Model: LOT PRE Ahead Of SR Or AR TC
Revised and updated from Fig. 13 of Bosart and Carr (1978)
PRE Outlook
Synoptic setting seemed somewhat favorable for potential PRE development poleward of Hanna TC embedded within southerly 700 mb flow, with short
wave upstream However, trough was less amplified than the composites
Strengthening upper-level jet streak to the north Developing 925 mb theta-e ridge, although a little
broader and farther east than the composites Proximity of low-level boundary
850 mb Moisture Transport, 0000 UTC, 6 Sept.
850 mb Moisture Transport, 1200 UTC, 6 Sept.
Precipitable Water and Low-Level Winds, 0000 UTC, 6 Sept.
Precipitable Water and Low-Level Winds, 1200 UTC, 6 Sept.
Radar Loop, 0000 – 1500 UTC, 6 Sept.
QPE, 0600-1200 UTC, 6 Sept.
“PRE-like” Rainfall
A Quick PRE
A band of heavy rainfall did develop north of Hanna from late Friday, 9/6 into Sat., 9/7 However, it was transient in nature; almost like
a progressive warm front feature Limited rainfall in most areas to 1” or less Parts of RI/southeast MA did get heavier amounts (2-
3” and locally higher, in just a 3-6 hour period)• Best combination of moisture inflow and jet dynamics
Hanna’s Direct Rainfall Shield
A narrow band of heavy rain accompanied Hanna up the Eastern Seaboard Maximum rainfall shifted increasingly just to the
left of track with poleward extent Typical of transitioning TC
Generally, 3-6” of rain fell within a 6-10 hour period
Dry antecedent conditions and the lack of a significant “Along-Track” PRE mitigated any serious flood problems
Radar Loop from 1200 UTC, 6 Sept. to 0600 UTC, 7 Sept.
QPE, 1200 UTC, 6 Sept. to 1200 UTC, 7 Sept.
Where heavier rains fell earlier
Ike
Ike Overview
Ike came ashore as a Category 2 Hurricane along the TX coast around 0600 UTC, 13 Sept.
Synoptic Back-drop: Large southeastern U.S. ridge and western
states troughiness Deep southerly flow regime over the southern Plains
and up the Mississippi Valley
700 mb Heights/Winds, 0600 UTC, 12 Sept.
925 mb Heights/Theta-E and 200 mb Winds, 0600 UTC, 12 Sept.
Theta-E Ridge Line
Ike Falls Within the CG Category; CG TC Tracks and PRE Locations
All CG Tracks All CG PPTC Tracks; with PRE centroids (colored dots)
PRE Outlook
Synoptic setting seemed favorable for potential PRE development poleward of Ike TC embedded within southerly 700 mb flow,
with trough upstream Strengthening upper-level jet streak to the
north/northeast Sharpening 925 mb theta-e ridge axis Nearly stationary low-level boundary
Derived Total Precipitable Water, 0600 UTC, 12 Sept.
Channel of Moisture Inflow
LIke
Precipitable Water, 0600 UTC, 12 Sept.
850 mb Moisture Transport, 0600 UTC, 12 Sept.
Radar Loop, 0000 – 1800 UTC, 12 Sept.
Parcel Trajectories
Red – About 850 mbBlue – About 700 mbGreen – About 500 mb
LIke
Total Rainfall for PRE in Southern KS
Flood Pictures (West Wichita, KS)
700 mb Analysis, 1200 UTC, 13 Sept.
L
Ike
300 mb Analysis, 1200 UTC, 13 Sept.
925 mb Analysis, 1200 UTC, 13 Sept.
L
Ike
850 mb Moisture Transport, 1200 UTC, 13 Sept.
Precipitable Water, 1200 UTC, 13 Sept.
Radar Loop, 0600-1800 UTC, 13 Sept.
Total Rainfall for PRE in Northern IL
Ike’s Significant PRE
Two well defined PRE First from central OK to southern KS late on
Thu., 9/11 and early Fri., 9/12 Widespread 6”+ rainfall, with an embedded
band of 10-15” (Wichita, KS set all-time 24-hour precipitation record (nearly 11”))
Second from northern MO/southeastern IA to northern IL/IN
Several bands of 5-10” rainfall (locally higher amounts)
Ike’s Direct Rainfall Shield
TC Ike picked up speed as it gained latitude A band of 3-6” rainfall spread from the southern
Plains, to the Mississippi Valley, to the Lower Great Lakes region
Fortunately for KS, most of this rainfall occurred east of the Wichita area
Parts of MO and IL not so lucky Exacerbated existing flood problems from the PRE
Radar Loop from 1800 UTC, 13 Sept. to 1200 UTC, 14 Sept.
QPE, from 0600-1200 UTC, 14 Sept.
Hardest hit areas from Ike’s first PRE
QPE, from 1200-1800 UTC, 14 Sept.
Hardest hit areas from Ike’s second PRE
Flood Pictures (Chicago area)
Summary
Fay produced very heavy rainfall; but no PRE Strong ridge to the north/northeast prevented significant moisture
advection outward from the TC’s circulation center Hanna produced a transient PRE-like feature to its north
Fast PRE movement kept rainfall amounts down Not much overlap between PRE and direct TC rainfall
Ike produced two substantial PRE Stationary forcing features (frontal boundary and back-building
upper-level jet) were better able to anchor/lift deep tropical moisture plume
PRE had considerably more impact than direct TC rainfall in KS
PRE + TC rainfall created major runoff problems in MO and IL
The End !!
Any Questions ??